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Hydrogen-rich PBS protects cultured human cells from ionizing radiation-induced cellular damage

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Hydroxyl radicals play an important role in ionizing radiation-induced cellular damage, while hydrogen can selectively reduce hydroxyl radicals in vitro. This study was designed to test the hypothesis that hydrogen-rich PBS may be an effective radioprotective agent in vitro. Compared to cells pretreated without hydrogen, we demonstrated that treating cells with hydrogen-rich PBS before irradiation could significantly inhibit IR-induced apoptosis, increase viability of human intestinal crypt cells, significantly increase endogenous antioxidant, and decrease malondialdehyde and 8-hydroxydeoxyguanosine concentrations of human lymphocyte AHH-1 cells. It is concluded that hydrogen has a potential as an effective and safe radioprotective agent.
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HY DRO GEN-RICH PBS PRO TECTS CUL TURED HU MAN
CELLS FROM ION IZ ING RA DI A TION-IN DUCED
CEL LU LAR DAM AGE
by
Liren QIAN 1, Bailong LI 1, Fei CAO, Yuecheng HUANG, Shulin LIU,
Jianming CAI*, and Fu GAO*
De part ment of Ra di a tion Med i cine, Fac ulty of Na val Med i cine,
Sec ond Mil i tary Med i cal Uni ver sity, Shang hai, P. R. China
Sci en tific pa per
UDC: 614.8.086.5:66.094.1
DOI: 10.2298/NTRP1001023Q
Hydroxyl rad i cals play an im por tant role in ion iz ing ra di a tion-in duced cel lu lar dam age, while
hy dro gen can se lec tively re duce hydroxyl rad i cals in vi tro. This study was de signed to test the
hy poth e sis that hy dro gen-rich PBS may be an ef fec tive radioprotective agent in vi tro. Com -
pared to cells pretreated with out hy dro gen, we dem on strated that treat ing cells with hy dro -
gen-rich PBS be fore ir ra di a tion could sig nif i cantly in hibit IR-in duced apoptosis, in crease vi -
a bil ity of human in tes ti nal crypt cells, sig nif i cantly in crease en dog e nous an ti ox i dant, and
de crease malondialdehyde and 8-hydroxydeoxyguanosine con cen tra tions of human lym pho -
cyte AHH-1 cells. It is con cluded that hy dro gen has a po ten tial as an ef fec tive and safe
radioprotective agent.
Key words: hy dro gen, ionizing ra di a tion, radioprotection, apoptosis, re ac tive ox y gen spe cies
IN TRO DUC TION
Hy dro gen is the most abun dant chem i cal el e -
ment. It is a col or less, odor less, non-me tal lic, taste -
less, highly flam ma ble di atomic gas which was con -
sid ered as a physiological in ert gas. Hy dro gen is
sel dom re garded as an im por tant agent in med i cal us -
age. Howerver, Ohsawa et al. [1] found that mo lec u -
lar hy dro gen could se lec tively re duce cytotoxic re ac -
tive ox y gen spe cies, such as ·OH and ONOO– in vi tro
and ex ert ther a peu tic an ti ox i dant ac tiv ity in a rat mid -
dle ce re bral ar tery oc clu sion model.
Re ac tive ox y gen spe cies (ROS) or re ac tive ni -
tro gen spe cies (RNS), such as hydroxyl rad i cal (·OH),
superoxide an ion (O2-), hy dro gen di ox ide (H2O2), ni -
tric ox ide (NO), peroxynitrite (ONOO-), ap pear to
play a crit i cal role in ce re bral, myo car dial and hepatic
ischemia-reperfusion injuries, trans plan ta tion in ju -
ries, and other in ju ries [2-4]. It has also been dem on -
strated that H2 is ef fec tive in the prevention of these in -
ju ries. How ever, the po ten tial ef fect of hy dro gen gas
on an other dam age type in which free radicals play an
im por tant role is largely ig nored. That type is the dam -
age in duced by ir ra di a tion.
Approximately 65% of the DNA dam age is
caused by the in di rect ef fect of free rad i cals, such as
hydroxyl rad i cals (·OH), that are formed from the
radiolysis of surrounding wa ter mol e cules and that
suc ces sively at tack DNA [5]. Lipid peroxidation
(LPO) is also con sid ered as a crit i cal event dur ing ion -
iz ing ra di a tion in duced dam age [6]. Apart from ge -
netic dam age and lipid peroxidation, ROS can also al -
ter the bal ance of en dog e nous pro tec tive sys tems such
as glutathione and en zy mic an ti ox i dant de fence sys -
tems [7] . The en dog e nous an ti ox i dant defences are in -
ad e quate to re duce the ra di a tion-in duced free rad i cal
changes. Ap pro pri ate an ti ox i dant in ter ven tion seems
to in hibit or re duce free rad i cal tox ic ity and thus of fers
pro tec tion against ra di a tion.
There fore, we rea soned that hydrogen might be
pro tec tive against det ri men tal ef fects of ra di a tion.
How ever, the ap pli ca tion of H2 gas in ha la tion is not
con ve nient and may be dan ger ous be cause the gas is
in flam ma ble and ex plo sive. On the other hand, H2 gas
sat u rated PBS, which is called hy dro gen-rich PBS, is
easy to ap ply and safe. In the cur rent study, we dem on -
strated that hy dro gen-rich PBS treat ment can pro tect
human cells from g-ra di a tion in vi tro.
L. Qian, et al.: Hy dro gen-Rich PBS Pro tects Cul tured Hu man Cells from ...
Nu clear Tech nol ogy & Ra di a tion Pro tec tion: Year 2010, Vol. 25, No. 1, pp. 23-29 23
*Cor re spond ing au thors; e-mails: cjm882003@ya hoo.com.cn
(J. Cai); gaofu_2002@ya hoo.com.cn (F. Gao)
1L. Qian and B. Li con trib ute equally to this paper
MA TE RI ALS AND METH ODS
Prep a ra tion of hy dro gen-rich PBS
Hy dro gen was be ing dis solved in PBS for 6
hours un der high pres sure (0.4 MPa) in or der to reach a
su per sat u rated level by us ing hy dro gen-rich wa -
ter-pro duc ing ap pa ra tus which was pro duced by our
de part ment. The sat u rated hy dro gen PBS was stored
un der the at mo spheric pres sure at 4 °C in an alu mi num
bag with no dead vol ume. Hy dro gen-rich PBS was
freshly pre pared ev ery week, which en sured that a
con cen tra tion of more than 0.6 mmol/L was main -
tained. Gas chro ma tog ra phy was used to con firm the
con tent of hy dro gen in PBS by the method de scribed
by Ohsawa, et al. [1].
Hy dro gen treat ment of cul tured cells
Hu man lym pho cyte AHH-1 cells and in tes ti nal
crypt HIEC cells were main tained in RPMI 1640
(Invitrogen) with 10% fe tal bo vine se rum and 1% pen -
i cil lin-strep to my cin-glutamine at 37 °C in a 5% CO2
hu mid i fied cham ber. For radioprotective stud ies, cells
were treated with different vol ume of hy dro gen-rich
PBS and ac cord ingly we added dif fer ent vol ume of
PBS in or der to ob tain the de sired con cen tra tion of H2
and make the fi nal vol ume of the me dium the same.
Then, the treated cells were im me di ately ir ra di ated
with dif fer ent doses of g-ray, de pend ing on the re -
quire ment of the pres ent study.
Ir ra di a tion
Co balt-60 gamma rays in irradiation cen ter
(Fac ulty of Na val Med i cine, Sec ond Mil i tary Med i cal
Uni ver sity, China) were used for the ir ra di a tion pur -
pose. Cells (with or with out hy dro gen pre-treat ment)
were ex posed to dif fer ent doses of ra di a tion, de pend -
ing on the re quire ment of the pres ent study.
Clonogenic sur vival
Col ony-form ing as say was per formed as pre vi -
ously de scribed [8]. Briefly, cal cu lated num bers of
cells were plated to en able nor mal iza tion for plat ing
ef fi cien cies. Pretreated cells were then ir ra di ated with
0, 2, 4, 6, or 8 Gy. Af ter in cu bat ing for 7 days, the
plates were fixed with 70 % EtOH and stained with 1%
meth y lene blue. Col o nies con sist ing of >50 cells were
counted un der mi cro scope. The sur vival frac tions
were cal cu lated as (num ber of col o nies / num ber of
cells plated) / (num ber of col o nies for cor re spond ing
con trol / num ber of cells plated).
Lac tate dehydrogenase (LDH) leak age as say
LDH leak age as say was car ried out us ing LDH
cytotoxicity de tec tion kit (Nanjing KeyGen Biotech.
Co. Ltd.) ac cord ing to the pro to col in the user’s man -
ual. Cells were pretreated with hy dro gen-rich PBS and
the fi nal con cen tra tion of H2 was main tained above
0.3 mmol/L. The cells were immediately ex posed to
gamma ra di a tion and then trans ported to an ice bucket.
Af ter 4 hour time pe riod we ana lysed the con tent of
LDH in cell sus pen sion.
Apoptosis as says for cul tured cells
Apoptosis was de ter mined by Annexin V-APC
and propidium io dide stain ing us ing apoptosis de tec -
tion kit (Bipec Biopharma). Treated cells were in cu -
bated with Annexin V-APC for 15 min utes at 4 °C and
propidium io dide for 5 min utes at room tem per a ture.
The cells were then an a lyzed by flow cytometry. Al ter -
na tively, apoptosis was de ter mined by Hochest33258,
flourescein diacetate (FDA) and propidium io dide
stain ing. The treated cells were washed with PBS
twice, and then stained with 40 mg/L flourescein
diacetate, 20 mg/L Hoechst33258 at room tem per a ture
for 15 min utes, and stained with 20 mg/L propidine io -
dine at room tem per a ture for 5 minutes. The cel lu lar
mor phol ogy was ob served us ing Olym pus BX60 flu o -
res cent mi cro scope equipped with Retiga 2000R dig i tal
cam era. The av er age per cent age of apoptotic cells was
cal cu lated in 5-7 ran domly se lected high power fields
(HPF).
De ter mi na tion of malondialdehyde (MDA)
superoxide (SOD) glutathione (GSH)
MDA is a break down prod uct of the ox i da tive
deg ra da tion of cell mem brane lipids and is gen er ally
con sid ered an in di ca tor of lipid peroxidation. SOD is a
scav en ger of superoxide, and GSH is an im por tant cel -
lu lar non-en zy matic an ti ox i dant. In the pres ent study,
4 hours after trans porting the ir ra di ated cells to an ice
bucket, the con cen tra tions of MDA, SOD, and GSH
were mea sured, re spec tively, by us ing the MDA,
SOD, GSH as say kit (Nanjing KeyGen Biotech. Co.
Ltd.) ac cord ing to the pro to cols in the user’s man ual.
De ter mi na tion of 8-OHdG con cen tra tion
Half an hour af ter the ir ra di a tion, the 8-OHdG
con cen tra tion was mea sured by us ing hu man 8-OHdG
elisa kit (Nanjing KeyGen Biotech. Co. Ltd.) ac cord -
ing to the pro to col in the user’s man ual. Briefly af ter
that, the treated cells were lysed by a cell lysis buffer.
Af ter the cen tri fuge, we added sus pen sion to plate
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24 Nu clear Tech nol ogy & Ra di a tion Pro tec tion: Year 2010, Vol. 25, No. 1, pp. 23-29
wells coated with hu man 8-OHdG an ti body, and se -
quen tially treated them with biotinylated anti-lgG and
streptavidin-HRP. Af ter that, we added TMB sub strate
so lu tion, and TMB sub strate changed color into blue at
HRP en zyme-cat a lyzed. At the ef fect of acid, the color
fi nally be come yel low. The in ten sity of this col ored
prod uct is di rectly pro por tional to the con cen tra tion of
8-OHdG. Mea sur ing the op ti cal den sity (OD) at 450
nm with a microtiter plate reader, we cal cu lated hu man
8-OHdG con cen tra tion by the stan dard curve.
STA TIS TI CAL ANAL Y SIS
Data are ex pressed as means ±S. E. M. (stan dard
er ror of the mean) for each ex per i ment. The num ber of
sam ples is in di cated in the de scrip tion of each ex per i -
ment. Sta tis ti cal anal y sis was per formed by us ing one
way anal y sis of vari ance. Be tween groups, vari ance
was de ter mined us ing the Stu dent-Newman-Keuls post
hoc test. A P value of less than 0.05 was con sid ered to be
sta tis ti cally sig nif i cant.
RE SULTS
Hy dro gen-rich PBS in creases clonogenic
sur vival of ir ra di ated HIEC cells
To study radioprotective ef fects of H2 in a cell cul -
ture, we ex am ined the vi a bil ity of the ir ra di ated hu man
in tes ti nal crypt (HIEC) cells us ing a clonogenic sur -
vival as say. Pre treat ment of HIEC cells with 0.1-0.4
mmol/L H2 be fore ir ra di a tion sig nif i cantly in creased
cell sur vival as com pared to the cells treated with ra di a -
tion alone at all ex am ined doses (up to 8 Gy), fig. 1(a).
Hy dro gen-rich PBS de crease cel lu lar lactate
dehydrogenase (LDH) leak age of ir ra di ated
HIEC cells
Be side the cell vi a bil ity, we also determined
LDH ac tiv i ties to es ti mate cel lu lar LDH leak age from
dam aged cells. The re sult in di cated that pre treat ment
with 0.3 mM H2 be fore ir ra di a tion sig nif i cantly de -
creased LDH leak age of HIEC cells which were ex -
posed to dif fer ent doses of g-ra di a tion, fig. 1(b). This
re sult too was con sis tent with the re sult ob tained by
cell vi a bil ity ob ser va tion.
Hy dro gen-rich PBS at tenu ates apoptosis in
ir ra di ated HIEC cells
To de ter mine the ra di a tion-in duced apoptosis of
the ir ra di ated HIEC cells, we an a lyzed the treated cells
by us ing Annexin V-APC and propidium io dide stain -
ing in flow cytometry as say. The early apoptotic cells
de creased when pretreated with hy dro gen-rich PBS as
com pared to the cells pretreated with PBS, fig. 2(a)
and (b), 10.2% vs. 21.5%, re spec tively). We fur ther
eval u ated the mor phol ogy of dy ing cells us ing
Hochest33258, flourescein diacetate and propidium
io dide stain ing. The ir ra di ated HIEC cells pretreated
with hy dro gen-rich PBS dem on strated a pro tec tive ef -
fect with the re duced num ber of apoptotic cells to
26.1% as com pared to 49.3% in PBS-pretreated ir ra di -
ated cells, fig. 2(c) and (d). These data sug gest that H2
can at ten u ate apoptosis in ir ra di ated HIEC cells.
Treating AHH-1 cells with hydrogen be fore
ir ra di a tion could in crease endogenous
an ti ox i dant sta tus
The lev els of en zy matic an ti ox i dants (SOD) and
the ac tiv i ties of non-en zy matic an ti ox i dant (GSH) are
shown in fig. 3. Gamma ir ra di ated lym pho cytes showed
a sig nif i cant de crease in the lev els of both en zy matic
and non-en zy matic an ti ox i dant sta tus when com pared
to hy dro gen-rich PBS pretreated groups. The re sults in -
di cated that pre treat ment with H2 could re store the an ti -
ox i dant sta tus.
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Fig ure 1. The treated HIEC cells were ir ra di ated with 0, 1,
2, 4, and 8 Gy and plated for clonogenic sur vival as say and
for LDH leak age as say; the sur viv ing frac tions (a) and
changes in the lev els of LDH in nor mal, g-ir ra di ated and
H2 pretreated lym pho cytes from three ex per i ments (b) are
shown; values are given as mean ±S. E. M. *P < 0.05
Hydrogen-rich PBS pro tects lipids and
nu clear DNA of AHH-1cells from
peroxidation in duced by ra di a tion
As shown in fig. 4(a), cel lu lar MDA con cen tra -
tion at 4 hours af ter the ir ra di a tion in the H2 group was
sig nif i cantly lower than that of the con trol group. This
re sult in di cated that H2 could pro tect lipids from
peroxidation in duced by ra di a tion. As shown in fig.
4(b), H2 com pa ra bly de creased the con cen tra tion of
8-OHdG rel a tive to the con trol group, in di cat ing that
H2 can pro tect DNA from peroxidation in duced by ra -
di a tion.
DIS CUS SION
This study shows that hy dro gen can sig nif i -
cantly pro tect hu man cells from ion iz ing ra di a tion. In -
ha la tion of H2 was re ported to pro tect ce re bral [1],
myo car dial [2], and hepatic [9] I/R in jury in an i mal
mod els in sev eral re cent stud ies. Also, it is re ported
that hy dro gen in ha la tion ame lio rates ox i da tive stress
in trans plan ta tion in duced in tes ti nal graft in jury [3].
Since most of the ion iz ing ra di a tion-in duced cel lu -
lar dam age is caused by hydroxyl rad i cals, we spec u late
that the radioprotective ef fect may re sult from its rad i cal
ox y gen spe cies (ROS) scav eng ing ef fect. It was re ported
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26 Nu clear Tech nol ogy & Ra di a tion Pro tec tion: Year 2010, Vol. 25, No. 1, pp. 23-29
Fig ure 2. Hy dro gen-rich PBS at tenu ates ra di a tion-in duced apoptosis in HIEC cells. The treated cells were col lected 24
hours af ter the ir ra di a tion, stained with Annexin V-APC and propidium io dide and an a lyzed by flow cytometry. The rep -
re sen ta tive di a grams of dis tri bu tion of the stained cells (a) and a bar graph of apoptotic cells ex pressed as a per cent of to tal
cells are shown. Val ues are given as mean ±S. E. M. (n = 4); *P < 0.01 (b); cells were stained with FDA, Hoechst33258 and
PI 24 hours af ter ir ra di a tion and apoptotic cells were counted in mul ti ple ran domly se lected fields. The rep re sen ta tive mi -
cro graphs (c) and a bar graph of apoptotic cells ex pressed as a per cent of to tal cells are shown; values are given as mean
±S. E. M. (n = 4); *P < 0.01 (d)
that the ef fect of free rad i cal scav en gers could ame lio rate
the ox i da tive in ju ries due to ion iz ing ra di a tion [10, 11].
The sulfhydryl com pound amifostine (WR-2721),
which is the only radioprotectant reg is tered in use for hu -
mans, has shown good radioprotective ef fects [12].
How ever, when it was ad min is tered by in jec tion, it
caused many neg a tive ef fects such as vom it ing, hy per -
ten sion, nau sea, and other side ef fects caused by the tox -
ic ity [13, 14]. Some other radioprotectors, such as nat u ral
an ti ox i dants, vi ta min E, flavonoids and oth ers, have
fewer toxic side ef fects but also a lower de gree of pro tec -
tion com pared to thiol agents [13], and cytokines and
immunomodulators should be used with low ra di a tion
doses or in com bi na tion with rad i cal scav en gers and an ti -
ox i dants [15]. How ever, it is phys i o log i cally safe for hu -
mans to in hale hy dro gen at a rel a tively low con cen tra -
tion, be cause hy dro gen is con tin u ously pro duced by
co lonic bac te ria in the body and nor mally cir cu lates in
the blood [16]. It is a highly diffusible gas which could
elim i nate hydroxyl rad i cal [17]. Dis solv ing H2 in sol -
vents such as PBS makes this ex plo sive gas more safe for
clin i cal use.
Rad i cal ox y gen spe cies O2 and H2O2 are de tox -
i fied by an ti ox i dant de fense en zymes, un like ·OH and
ONOO, which so far could not be detoxified by any
an ti ox i dant de fense en zyme. Hy dro gen gas se lec -
tively re duces these two det ri men tal ROS [1]. A
hydroxyl rad i cal is the most re ac tive prod uct of re ac -
tive ox y gen spe cies gen er ated in cells. Cellular
macromolecules, such as DNA, pro teins, and lipids,
can eas ily re act with hydroxyl rad i cals to ex ert a
cytotoxic ef fect.
An ti ox i dant en zymes (SOD) are im por tant in
pro vid ing pro tec tion from ra di a tion ex po sure [18] and
glutathione (GSH) par tic i pates non-en zy mat i cally in
pro tec tion against ra di a tion dam age [19]. En dog e nous
an ti ox i dants are a group of sub stances which could
sig nif i cantly in hibit or de lay ox i da tive pro cesses [20].
A num ber of harms can re sult from a re duc tion of the
ac tiv ity of these sub stances. DNA is one of the ma jor
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Fig ure 3. Changes in the ac tiv i ties of SOD and GSH in nor mal, g-ir ra di ated, and H2 pretreated lym pho cytes; values are
given as mean ±S. E. M. (n = 4); *P < 0.01.
Fig ure 4. Hy dro gen-rich PBS sig nif i cantly de creased the lev els of MDA, a marker of ox i da tive stress (a), and ox i da tive
DNA dam age as sessed by 8-OHdG immunoreactivity. 8-OHdG con cen tra tion in nor mal, g-ir ra di ated, and H2 pretreated
groups (b) half an hour af ter the ir ra di a tion are shown; rel a tive to the con trol group, H2 sig nif i cantly de creased the con -
cen tra tion of 8-OHdG; val ues are mean ±S. E. M. (n = 6); *P < 0.01.
tar gets of free rad i cals, and 8-OHdG is formed from
deoxyguanosine in DNA by hydroxyl free rad i cals
[21]. Also, mem brane lipids are the ma jor tar gets of
free rad i cals [22]. The in crease in the lev els of lipid
peroxidation prod ucts such as malondialdehyde and
TBARs is the in di ca tion of mem brane lipid dam age
[23]. In our study, we found that the pretreatment of
hy dro gen-rich PBS prior to ra di a tion ex po sure in -
creased the an ti ox i dant sta tus at both en zy mic and
non-en zy mic lev els and de creased the levels of MDA
and 8-OHdG com pared with the cells pretreated with -
out hy dro gen-rich PBS. We may con clude that the in -
creases of the an ti ox i dant sta tus have fur ther de -
creased the at tack of free rad i cals on biomolecules
in clud ing DNA and mem brane lipids and thereby de -
creased the del e te ri ous ef fects of ra di a tion on cells.
In con clu sion, hy dro gen-rich PBS could pro tect
hu man cells from ra di a tion. This radioprotective ef -
fect may re sult from its rad i cal ox y gen spe cies scav -
eng ing ef fect. Dis solv ing hy dro gen in so lu tion (PBS,
wa ter, sa line) makes it safer and more con ve nient to
use in clinic. We be lieve that hy dro gen gas, es pe cially
hy dro gen-rich so lu tion, may give us more hope for
greater pro tec tion from ir ra di a tion.
AC KNOWL EDGE MENTS
This work was sup ported by a grant from the Na -
tional Nat u ral Sci ence Foun da tion of China (No.
30770503).
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28 Nu clear Tech nol ogy & Ra di a tion Pro tec tion: Year 2010, Vol. 25, No. 1, pp. 23-29
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Res, 47 (1995), pp. 265-270
Re ceived on Sep tem ber 3, 2009
Ac cepted on Feb ru ary 8, 2010
L. Qian, et al.: Hy dro gen-Rich PBS Pro tects Cul tured Hu man Cells from ...
Nu clear Tech nol ogy & Ra di a tion Pro tec tion: Year 2010, Vol. 25, No. 1, pp. 23-29 29
Liren ]EN, Bailung LI, Fei CAO, @u~eng HUANG,
[ulin LIU, \enming CAI, Fu GAO
PBS OBOGA]EN VODONIKOM [TITI ^OVE^IJE ]ELIJE U
KULTURI OD ZRA^EWEM NANETIH OZLEDA
Vodoni~ni radikali imaju zna~ajnu ulogu u indukciji }elijskih ozleda dejstvom
jonizuju}eg zra~ewa. Molekularni vodonik mo`e selektivno da smawi koncentraciju
hidroksilnih radikala in vi tro. Takve osobine ~ine ga potencijalnim radioprotektorom. U ovom
radu testirana su radioprotektivna svojstva vodonika in vi tro kori{}ewem PBS oboga}enog
vodonikom. Tretirawe }elija s PBS oboga}enim vodonikom, pre ozra~ivawa, zna~ajno smawuje
apoptozu indukovanu jonizuju}im zra~ewem, pove}ava vitalnost i pre`ivqavawe ozra~enih
kripti~nih }elija tankog creva (HIEC), pove}ava koncentraciju endogenih antioksidanata i
smawuje koncentraciju 8-hidroksideoksiguanozin-malondialdehida u limfocitima (AHH-1
}elije). Iz dobijenih rezultata mo`e se zakqu~iti da vodonik poseduje zna~ajnu osobinu
radioprotektora: efikasan je i nema ne`eqenih svojstava.
Kqu~ne re~i: vodonik, jonizuju}e zra~ewe, za{tita od zra~ewa, apoptoza, reaktivne
jjjjjjjjjjjjjjj.jjjjjjjjkiseoni~ne vrste
... Experimentally, hydrogen has been used to protect against various types of radiation damage in a variety of animal tissues [212]. Some examples are: skin [219]- [221], intestine [216], lung [111] [212], heart [91] [216], brain [212] [222], bone marrow [216] [223] [224], testis [218] [247], and other tissues [212]. Of special clinical importance is the radioprotection of radiation-sensitive tissues, such as bone marrow, because these are the most likely to be damaged by radiation [212]. ...
... For example, treatment of human intestinal crypt cells, with or without hydrogen-rich phosphate-buffered saline before exposure to gamma radiation (up to 8 Gy), resulted in significant reduction of radiation-induced apoptosis and an increase in viability in the H 2 -enriched phosphate-buffered saline-treated cells [224]. In contrast, if the cells were treated with the H 2 -phosphate-buffered saline after radiation exposure, then the protective effects of hydrogen were not seen [224]. ...
... For example, treatment of human intestinal crypt cells, with or without hydrogen-rich phosphate-buffered saline before exposure to gamma radiation (up to 8 Gy), resulted in significant reduction of radiation-induced apoptosis and an increase in viability in the H 2 -enriched phosphate-buffered saline-treated cells [224]. In contrast, if the cells were treated with the H 2 -phosphate-buffered saline after radiation exposure, then the protective effects of hydrogen were not seen [224]. Hydrogen has also been used in cancer therapy. ...
Article
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Here we review the literature on the effects of molecular hydrogen (H2) on normal human subjects and patients with a variety of diagnoses, such as metabolic, rheumatic, cardiovascular and neurodegenerative and other diseases, infections and physical and radiation damage as well as effects on aging and exercise. Although the effects of H2 have been studied in multiple animal models of human disease, such studies will not be reviewed in depth here. H2 can be administered as a gas, in saline implants or infusions, as topical solutions or baths or by drinking H2-enriched water. This latter method is the easiest and least costly method of administration. There are no safety issues with hydrogen; it has been used for years in gas mixtures for deep diving and in numerous clinical trials without adverse events, and there are no warnings in the literature of its toxicity or longterm exposure effects. Molecular hydrogen has proven useful and convenient as a novel antioxidant and modifier of gene expression in many conditions where oxidative stress and changes in gene expression result in cellular damage.
... As for the radioprotective effects of H 2 in animal models, protective effects on cognitive function, the immune system, lungs, heart, digestive organs, hematopoietic organs, testis, skin, and cartilage disorders have been reported [36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53]. An inhibitory effect on thymic lymphoma caused by radiation has also been reported [54]. ...
... [43] Gastrointestinal damage HIEC H 2 -rich PBS inhibited apoptosis and increased the cell viability of HIEC. [37] Mice H 2 -rich saline protected against radiation-induced gastrointestinal disorders. [38] Mice H 2 water ameliorated radiation-induced gastrointestinal toxicity. ...
... Radiation often causes the depletion of immune cells in tissues and blood, which leads to immunosuppression. Qian et al. reported the radioprotective effect of H 2 on cultured human lymphocyte (AHH-1) cells [37]. Pretreatment with H 2 -rich PBS (1.2 ppm) prior to irradiation significantly reduced the levels of MDA and 8-OHdG in AHH-1 cells compared to untreated controls [37]. ...
Article
Full-text available
Although ionizing radiation (radiation) is commonly used for medical diagnosis and cancer treatment, radiation-induced damages cannot be avoided. Such damages can be classified into direct and indirect damages, caused by the direct absorption of radiation energy into DNA and by free radicals, such as hydroxyl radicals (�OH), generated in the process of water radiolysis. More specifically, radiation damage concerns not only direct damages to DNA, but also secondary damages to non-DNA targets, because low-dose radiation damage is mainly caused by these indirect effects. Molecular hydrogen (H2) has the potential to be a radioprotective agent because it can selectively scavenge �OH, a reactive oxygen species with strong oxidizing power. Animal experiments and clinical trials have reported that H2 exhibits a highly safe radioprotective effect. This paper reviews previously reported radioprotective effects of H2 and discusses the mechanisms of H2, not only as an antioxidant, but also in intracellular responses including anti-inflammation, anti-apoptosis, and the regulation of gene expression. In doing so, we demonstrate the prospects of H2 as a novel and clinically applicable radioprotective agent.
... Several investigations of animal tissues have demonstrated that H 2 protects against detrimental effects of radiation, further indicating that H 2 acts as an effective radio-protective agent (Qian et al. 2010a(Qian et al. , 2010b. Results from the clinical trials also indicated that H 2 therapy may be an effective and specific novel treatment for acute radiation syndrome (Liu et al. 2010), and may reduce the risks related to radiation-induced oxidative stress in space flight (Schoenfeld et al. 2011). ...
... Results from the clinical trials also indicated that H 2 therapy may be an effective and specific novel treatment for acute radiation syndrome (Liu et al. 2010), and may reduce the risks related to radiation-induced oxidative stress in space flight (Schoenfeld et al. 2011). For example, the pretreatment with hydrogen-rich phosphate buffer saline could significantly inhibit gamma-ray irradiation-induced apoptosis of human intestinal crypt cells (Qian et al. 2010b). Hydrogen-rich saline protected mice from radiation-induced thymic lymphoma as well (Zhao et al. 2011). ...
Article
Full-text available
External administration of hydrogen gas (H2) benefits plants from multiple environmental stimuli. However, the physiological significance and molecular mechanism of H2 in ultraviolet-B (UVB) irradiation are largely unexplored. Here, the biological function of H2 in the regulation of plant UVB-tolerance was investigated by using hydrogen-rich water (HRW). Results showed that the exposure of alfalfa seedlings to UVB irradiation increased endogenous H2 production. Pretreatment with HRW mimicked the UVB-induced endogenous H2 production. Corresponding UVB-triggered toxic symptoms, in terms of lipid peroxidation and overproduction of reactive oxygen species (ROS), as well as the subsequent growth inhibition, were markedly mitigated. Metabolic profiling analysis by using ultra performance liquid chromatography-mass spectrometric (UPLC-MS), identified 40 (iso)flavonoids in UVB-treated alfalfa plants, with 22 kinds was increased by HRW. These changes resulted in the alternation of (iso)flavonoids profile, with the effective promotion of isoflavone and flavanone subfamilies in particular. These compounds included afromosin, afromosin 7-O-β-D-glucoside-malonate, daidzein, formononetin 7-O-β-D-glucoside-6-O-malonate, garbanzol, matteucin and naringenin. In vitro tests further showed that the HRW-modulated (iso)flavonoids profile upon UVB stress possessed advanced ROS-quenching and antioxidant capacities under our experimental conditions. Meanwhile, UVB-triggered upregulation in the transcription levels of (iso)flavonoids biosynthetic-related genes were substantially strengthened by HRW. The activities and related transcripts of representative antioxidant enzymes were also induced. Taken together, our findings indicate that HRW confers tolerance to UVB-induced oxidative damage partially by the manipulation of (iso)flavonoids metabolism and antioxidant defence in Medicago sativa L.
... Although the vast majority of potential mechanisms of action remain to be elucidated, it has been revealed that H2 exerts its beneficial effects through antioxidant, anti-inflammatory, and antiapoptotic effects, thus providing cytoprotection [8]. The protective effects of H2 on pathological conditions have been investigated using animal models of fibrotic heart disease [9], hepatic fibrosis [10], cerebral ischemia [11], radiation injury [12], and diabetes [13], in which intracellular accumulation of ROS is essentially involved in their pathogenesis. ...
... To test whether the hydrogen-enriched PBS could be used as an effective radioprotectant, a study by Qian et al. [85] was designed and analyzed in vitro. Human lymphocyte AHH-1 cells and intestinal crypt HIEC cells were treated with respective volume of hydrogen-enriched PBS and then were irradiated with corresponding doses of γ-ray. ...
Article
Full-text available
In recent years, many studies have shown that hydrogen has therapeutic and preventive effects on various diseases. Its selective antioxidant properties were well noticed. Most of the ionizing radiation-induced damage is caused by hydroxyl radicals (% OH) from radiolysis of H O 2. Since hydrogen can mitigate such damage through multiple mechanisms, it presents noteworthy potential as a novel radio-protective agent. This review analyses possible mechanisms for hydrogen's radioprotective properties and effective delivery methods. We also look into details of vitro and vivo studies for hydrogen's radioprotective effects, and clinical practices. We conclude that hydrogen has good potential in radio-protection, with evidence that warrants greater research efforts in this field.
... These therapeutic effects of molecular hydrogen are important in mediating the cytoprotection against radiotherapy and chemotherapy. Hydrogen has been shown to exert radioprotective effects on cultured cells and mice [25,164]. For example, in irradiated animals, the lipid peroxidation marker MDA was significantly increased in the small intestine, but was not similarly elevated in the hydrogen-water group [165]. ...
... These therapeutic effects of molecular hydrogen are important in mediating the cytoprotection against radiotherapy and chemotherapy. Hydrogen has been shown to exert radioprotective effects on cultured cells and mice [25,164]. For example, in irradiated animals, the lipid peroxidation marker MDA was significantly increased in the small intestine, but was not similarly elevated in the hydrogen-water group [165]. ...
Article
Full-text available
Cardiovascular diseases are the most common causes of morbidity and mortality worldwide. Redox dysregulation and a dyshomeostasis of inflammation arise from, and result in, cellular aberrations and pathological conditions, which lead to cardiovascular diseases. Despite years of intensive research, there is still no safe and effective method for their prevention and treatment. Recently, molecular hydrogen has been investigated in preclinical and clinical studies on various diseases associated with oxidative and inflammatory stress such as radiation-induced heart disease, ischemia-reperfusion injury, myocardial and brain infarction, storage of the heart, heart transplantation, etc. Hydrogen is primarily administered via inhalation, drinking hydrogen-rich water, or injection of hydrogen-rich saline. It favorably modulates signal transduction and gene expression resulting in suppression of proinflammatory cytokines, excess ROS production, and in the activation of the Nrf2 antioxidant transcription factor. Although H 2 appears to be an important biological molecule with anti-oxidant, anti-inflammatory, and anti-apoptotic effects, the exact mechanisms of action remain elusive. There is no reported clinical toxicity; however, some data suggests that H 2 has a mild hormetic-like effect, which likely mediate some of its benefits. The mechanistic data, coupled with the pre-clinical and clinical studies, suggest that H 2 may be useful for ROS/inflammation-induced cardiotoxicity and other conditions.
... Hydrogen has favorable distribution characteristics: it can penetrate biomembranes and diffuse into the cytosol, mitochondria and nucleus to reduce cytotoxic radicals. Hydrogen had been found to be a new class of radioprotective agent and it had protective effects on different systems, such as bone marrow (12) , intestine (13) , skin (14) , Testis (12,15) , lung (16,17) , skin (14) , and heart (18) etc. AM is taken up into the normal tissues and dephosphorylated by membrane-bound alkaline phosphatase to WR-1065, which is the active metabolite of radioprotection. Radiation survival is a result of several factors, such as the prevention of damage through the inhibition of free free-radical generation; ef<icient scavenging of free radicals; repair of DNA, membrane and other damaged target molecules and the replenishment of severely damaged or dead cells (19) . ...
Article
Background: Hydrogen has been demonstrated can selectively reduce the hydroxyl, which is the main cause of ionizing radiation-induced damage. Amifostine (AM) is the only radioprotective drug approved by the U.S. Food and Drug Administration for use in radiotherapy. The purpose of the present study was to investigate the combined radio-protective effect of hydrogen rich water (HRW) and AM. Materials and Methods: Male ICR mice were treated intragastrically with HRW or/and intraperitoneally with AM 30 minutes prior to 9.0 Gy whole body irradiation from a⁶⁰Co source (dose rate 0.96Gy/min). Then the survival rate for 30 days, the hematological parameters, the Clinical chemistry parameters and the bone marrow nucleated cells were examined. Results: We found that the mice treated with HRW and AM before irradiaion could increase the 30-day survival rate and improve the body weight better than the HRW or AM treatment alone group and irradiaion alone group. Hematological test and Clinical chemistry assays also showed the same results that HRW combined AM could beter improve the recovery of hemopoietic system and alleviate the detrimental effects of radiation. Conclusion: The results indicate that the combined application of HRW and AM may be a beter method for radiaion therapy. © 2016, Novim Medical Radiation Institute. All rights reserved.
... Aplastic anemia [231] Maintenance of multipotential stroma/mesenchymal stem cells [232] Neutrophil function [233] Inhibition of collagen-induced platelet aggregation [234] Improvement of blood fluidity [235] Metabolism Diabetes mellitus [236][237][238][239][240][241] Metabolic syndrome [245][246][247] Metabolic process-related gene expression [248] Oxidized low density lipoprotein-induced cell toxicity [54] Serum alkalinization [249] Exercise-induced metabolic acidosis [250] Inflammation/Allergy LPS-induced inflammatory response [90] LPS-induced vascular permeability [80,256] Zymosan-induced inflammation [257] Carrageenan-induced paw edema [258] Inflammatory response of cardiopulmonary bypass [259] Type Radiation-induced thymic lymphoma [267] Tumor angiogenesis [268] Enhancement of 5-FU antitumor efficacy [269] Radiation Cardiac damage [270] Lung damage [271] Testicular damage [272] Skin damage [273,274] Germ, hematopoietic and other cell damage [275][276][277][278][279][280] Radiation-induced adverse effects [281] Radiation-induced immune dysfunction [282] Intoxication Carbon monoxide [283][284][285][286] Sevoflurane [287,288] Doxorubicin-induced heart failure [289] Melamine-induced urinary stone [290] Chlorpyrifos-induced neurotoxicity [291] Transplantation regulators and achieve beneficial biological effects against oxidative stress, inflammation, apoptosis, and dysmetabolism to name a few (Fig. 3). These studies all point to the notion that hydrogen modulates intracellular signal transduction systems and regulates the downstream gene expressions to mitigate disease processes. ...
Article
Full-text available
Therapeutic effects of molecular hydrogen for a wide range of disease models and human diseases have been investigated since 2007. A total of 321 original articles have been published from 2007 to June 2015. Most studies have been conducted in Japan, China, and the USA. About three-quarters of the articles show the effects in mice and rats. The number of clinical trials is increasing every year. In most diseases, the effect of hydrogen has been reported with hydrogen water or hydrogen gas, which was followed by confirmation of the effect with hydrogen-rich saline. Hydrogen water is mostly given ad libitum. Hydrogen gas of less than 4 % is given by inhalation. The effects have been reported in essentially all organs covering 31 disease categories that can be subdivided into 166 disease models, human diseases, treatment-associated pathologies, and pathophysiological conditions of plants with a predominance of oxidative stress-mediated diseases and inflammatory diseases. Specific extinctions of hydroxyl radical and peroxynitrite were initially presented, but the radical-scavenging effect of hydrogen cannot be held solely accountable for its drastic effects. We and others have shown that the effects can be mediated by modulating activities and expressions of various molecules such as Lyn, ERK, p38, JNK, ASK1, Akt, GTP-Rac1, iNOS, Nox1, NF-κB p65, IκBα, STAT3, NFATc1, c-Fos, and ghrelin. Master regulator(s) that drive these modifications, however, remain to be elucidated and are currently being extensively investigated.
Article
Full-text available
Ionizing radiation is commonly used in the treatment of brain tumors but it can impair cognitive functions, such as learning and memory. Since cognitive dysfunctions are predominantly result of cell death by apoptosis in hippocampal cells, in this study we analyzed acute effects of cranial gamma-irradiation (10 Gy) on expression of proapoptotic molecules (p53, Bax) and antiapoptotic molecule Bcl-2, as well as caspase-3 activation and cytochrome c redistribution in the hippocampus of young rats. The selected regimen of irradiation resembles the established animal model for childhood prophylactic cranial radiotherapy. Our results demonstrated that p53 mRNA expression was unchanged after irradiation, while induction of p53 protein was rapid. In parallel, Bax mRNA and protein levels were also increased following irradiation, whereas Bcl-2 expression was not changed during the examined post-irradiation period. These changes were accompanied with early hallmarks of apoptosis, such as increased cytochrome c release and stimulated activation of caspase-3. Overall, this study demonstrates that cranial irradiation is associated with the augmented apoptotic pathway in the rat hippocampus, which could be related to the cognitive decline observed in patients after prophylactic cranial radiotherapy, but also opens perspective in finding radioprotectors that can mitigate radiation injury of normal brain tissue.
Article
The present study was aimed to evaluate the radioprotective efficacy of hesperidin (HN), a flavonone glycoside against gamma-radiation-induced cellular damage in cultured human peripheral blood lymphocytes. Different concentrations of HN (3.27, 6.55, 9.83, 13.10, 16.38 and 19.65 microM) were pre-incubated with lymphocytes for 30 min prior to gamma-irradiation [4 Gy] and the micronuclei (MN) scoring, dicentric aberration and comet assay were performed to fix the effective dose of HN against gamma-irradiation induced cellular damage. The results indicated that among all the concentrations, 16.38 microM concentration of HN showed optimum protection by effectively decreasing the MN frequencies, dicentric aberrations and comet attributes. Based on the above results, 16.38 microM concentration of HN was fixed as the effective dose to further investigate its radioprotective efficacy which was then carried out by pre-incubating lymphocytes with 16.38 microM concentration of HN, exposing the lymphocytes to different doses (1, 2, 3 and 4 Gy) of radiation and investigating radiation induced genetic damage (MN, dicentric aberration, comet assay, DNA fragmentation assay) and biochemical changes (changes in the level of enzymic and non-enzymic antioxidants, lipid peroxidation). The results indicated a dose dependent increase in both genetic damage and thiobarbituric acid reactive substances (TBARS), accompanied by a significant decrease in the antioxidant status compared to HN treated groups which modulated the toxic effects through its antioxidant potential. Thus the current study shows HN to be an effective radioprotector against gamma-radiation induced in-vitro cellular damage in lymphocytes.
Article
Ischemia/reperfusion (I/R) injury during small intestinal transplantation (SITx) frequently causes complications including dysmotility, inflammation and organ failure. Recent evidence indicates hydrogen inhalation eliminates toxic hydroxyl radicals. Syngeneic, orthotopic SITx was performed in Lewis rats with 3 h of cold ischemic time. Both donor and recipient received perioperative air or 2% hydrogen inhalation. SITx caused a delay in gastrointestinal transit and decreased jejunal circular muscle contractile activity 24 h after surgery. Hydrogen treatment resulted in significantly improved gastrointestinal transit, as well as jejunal smooth muscle contractility in response to bethanechol. The transplant induced upregulation in the inflammatory mediators CCL2, IL-1 beta, IL-6 and TNF-alpha were mitigated by hydrogen. Hydrogen significantly diminished lipid peroxidation compared to elevated tissue malondialdehyde levels in air-treated grafts demonstrating an antioxidant effect. Histopathological mucosal erosion and increased gut permeability indicated a breakdown in posttransplant mucosal barrier function which was significantly attenuated by hydrogen treatment. In recipient lung, hydrogen treatment also resulted in a significant abatement in inflammatory mRNA induction and reduced neutrophil recruitment. Hydrogen inhalation significantly ameliorates intestinal transplant injury and prevents remote organ inflammation via its antioxidant effects. Administration of perioperative hydrogen gas may be a potent and clinically applicable therapeutic strategy for intestinal I/R injury.
Article
d-Alpha-tocopherol (2R,4'R,8'R-Alpha-tocopherol) and d-alpha-tocotrienol are two vitamin E constituents having the same aromatic chromanol "head" but differing in their hydrocarbon "tail": tocopherol with a saturated and toctrienol with an unsaturated isoprenoid chain. d-Alpha-tocopherol has the highest vitamin E activity, while d-alpha-tocotrienol manifests only about 30% of this activity. Since vitamin E is considered to be physiologically the most important lipid-soluble chain-breaking antioxidant of membranes, we studied alpha-tocotrienol as compared to alpha-tocopherol under conditions which are important for their antioxidant function. d-Alpha-tocotrienol possesses 40-60 times higher antioxidant activity against (Fe2+ + ascorbate)- and (Fe2+ + NADPH)-induced lipid peroxidation in rat liver microsomal membranes and 6.5 times better protection of cytochrome P-450 against oxidative damage than d-alpha-tocopherol. To clarify the mechanisms responsible for the much higher antioxidant potency of d-alpha-tocotrienol compared to d-alpha-tocopherol, ESR studies were performed of recycling efficiency of the chromanols from their chromanoxyl radicals. 1H-NMR measurements of lipid molecular mobility in liposomes containing chromanols, and fluorescence measurements which reveal the uniformity of distribution (clusterizations) of chromanols in the lipid bilayer. From the results, we concluded that this higher antioxidant potency of d-alpha-tocotrienol is due to the combined effects of three properties exhibited by d-alpha-tocotrienol as compared to d-alpha-tocopherol: (i) its higher recycling efficiency from chromanoxyl radicals, (ii) its more uniform distribution in membrane bilayer, and (iii) its stronger disordering of membrane lipids which makes interaction of chromanols with lipid radicals more efficient. The data presented show that there is a considerable discrepancy between the relative in vitro antioxidant activity of d-alpha-tocopherol and d-alpha-tocotrienol with the conventional bioassays of their vitamin activity.
Article
Albino rats were treated with aqueous vitamin C solution and vitamin E solution dissolved in olive oil at two concentrations, 100 and 300 mg/kg/day, for 6 months. Some of the animals were then subjected to whole-body irradiation. Chromosomal aberrations and mitotic activity in non-irradiated and irradiated groups were recorded. Both vitamins were found to be non-mutagenic. Vitamin C exerted a radioprotective effect but vitamin E was not radioprotective and it suppressed the radioprotection otherwise produced by olive oil.
Article
The effectiveness of chemiluminescence (ChL) in vitro to measure free radicals generated as a result of metabolic disorganization caused by radiation sickness is evaluated. The results are correlated with those obtained by measuring superoxide dismutase (SOD) activity and lipid peroxide as levels of thiobarbituric acid reacting substances (TBARS). To this aim, livers from irradiated Wistar rats were removed immediately (day 0) after irradiation and also 7 and 14 d later. ChL results, expressed in arbitrary units (AU)/min/mg protein, were analyzed for irradiated samples and controls, for different doses at different times. Increased levels of ChL emission were observed not only on day 0, but also on days 7 and 14. On the other hand, SOD activity showed a decrease on the 7th d, and significantly higher lipid peroxide levels were observed in the assays performed on the 14th d, at all exposure doses. The correlation between temporal changes in the SOD activity, ChL emission, and higher TBARS levels a week later were evident from the data. These results indicate that the ChL technique proved to be useful in combination with other techniques currently used for evaluating radiation oxidative injury.
Article
8-hydroxy-2'-deoxyguanosine (8-OH-dG) was first reported in 1984 as a major form of oxidative DNA damage product by heated sugar, Fenton-type reagents and X-irradiation in vitro. 8-OH-dG has been detected in cellular DNA using an HPLC-ECD method in many laboratories. Analyses of 8-OH-dG in animal organ DNA after the administration of oxygen radical-forming chemicals will be useful for assessments of their carcinogenic risk. Its analysis in human leucocyte DNA and in urine is a new approach to the assessment of an individual's cancer risk due to oxidative stress. The increase of the 8-OH-dG level in the cellular DNA, detected by HPLC-ECD method, was supported by its immunochemical detection and its enhanced repair activity. The validity of the general use of 8-OH-dG as a marker of cellular oxidative stress is discussed.
Article
We examined the elevation of glutathione (GSH) level in mouse liver and HepG2 cells after low-dose gamma-ray irradiation and its inhibitory effect on acetaminophen (AAP)- and cumene hydroperoxide (CHP)-induced hepatotoxicity. The liver GSH level in male ddY mice increased 2 hours after irradiation with 50 cGy of gamma-rays, reached a maximum at around 4 hours and returned almost to the control level by 12 hours. The effect of irradiation at 2 hours before AAP-treatment on the hepatotoxicity was then investigated in terms of glutamic pyruvic transaminase (GPT) activity in serum and lipid peroxide (malondialdehyde, MDA) content in the liver. GPT activity and MDA level were markedly increased at 24 hours post-treatment with AAP. Both increases were significantly suppressed by a single low-dose pre-irradiation with gamma-rays (50 cGy). The cellular GSH level of HepG2 cells increased about 3 hours after exposure to gamma-rays (50 cGy), peaked at 12 hours and returned almost to the time 0 value by 48 hours post-irradiation. Exposure of HepG2 cells to CHP induced time- and dose-dependent cytotoxicity, as judged from lactate dehydrogenase activity (LDH) released into the medium. Pre-irradiation with gamma-rays (50 cGy) at 6 hours before addition of 1 mM CHP to the cells significantly suppressed the elevation of LDH activity at 24 hours post-treatment. In both cases, the lowered GSH levels induced by AAP and CPH appeared to be restored to the control level by pre-irradiation with a low dose of gamma-rays. These results suggest that low-dose gamma-ray irradiation might be effective for the prevention of hepatotoxicity involving GSH deficiency.
Article
In order to determine if age and comorbidity influence the tolerability of the cytoprotective agent amifostine, we compared side effects related to amifostine in patients > or = 70 years (group I) with patients < 70 years (group II). We evaluated 268 consecutive administrations of amifostine (119 in group I and 149 in group II, respectively), given i.v. at a dose of 740 mg/m(2) just before platinum-, taxol- or cyclophosphamide-based chemotherapy. Transient hypotension was the most common side effect occurring in association with amifostine. Decreases in systolic blood pressure > 20 mmHg were of similar frequency in both groups (27.1 versus 28.8% of amifostine infusions in group I and II, respectively). Hypotension did not result in medical sequelae in any of the patients. The amifostine infusion was interrupted 16 times in group I and 8 times in group II, respectively, mainly due to hypotension, but could be restarted after a few minutes in all patients except for three cases in group I. Patients in group II more often suffered from nausea/vomiting than in group II (20.8 versus 10.0% in group I). Other subjective symptoms (e.g. warmed, flushed sensation, sneezing, metallic taste, mouth dryness, dizziness and sleepiness) and hypocalcemia occurred with a similar frequency in both groups. Adverse effects associated with amifostine were not observed more frequently in elderly patients than in younger ones, although more elderly patients had a comorbidity than the younger ones.
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Oxidants such as H2O2 are connected to lymphocyte activation, but the molecular mechanisms behind this phenomenon are less clear. Here, I review data suggesting that by inhibiting protein tyrosine phosphatases, H2O2 plays an important role as a secondary messenger in the initiation and amplification of signaling at the antigen receptor. These findings explain why exposure of lymphocytes to H2O2 can mimic the effect of antigen. In addition, more recent data show that antigen receptors themselves are H2O2-generating enzymes and that the oxidative burst in macrophages seems to play a role not only in pathogen killing but also in the activation of these as well as neighboring cells. Thus, by controlling the activity of the negative regulatory phosphatases inside the cell, H2O2 can set and influence critical thresholds for lymphocyte activation.