[Show abstract][Hide abstract]ABSTRACT: To examine if isoflurane preconditioning can attenuate ischemia/reperfusion injury by reducing cytochrome c release from inner mitochondrial membrane.
Isolated hearts of Sprague-Dawley rats were perfused on Langendorff apparatus. Hearts were randomly assigned to a non-treated group (CON group, n=12) or three isoflurane preconditioning groups (0.5% ISC group, 1.0% ISC group, and 2.0% ISC group; n=12). In the latter three groups, isoflurane was given at concentrations of 0.5%, 1.0%, and 2.0% for 15 min with 15-min washout before 30-min ischemia. Subsarcolemmal mitochondria of the myocardium were isolated after 60-min reperfusion. Hemodynamics of the each heart was recorded, infarct size of the hearts and contents of cytosolic cytochrome or mitochondrial cytochrome c were measured at the end of reperfusion. Morphology of isolated mitochondria in the four groups was evaluated, respectively.
Compared with the CON group, cytosolic cytochrome c in 0.5% ISC group, 1.0% ISC group, and 2.0% ISC group were significantly decreased along with a significant increase of mitochondrial cytochrome c. Infarct size of the hearts in the four groups were 56%+/-12%, 41%+/-12%, 32%+/-7% and 33%+/-11%, respectively. The values of the three isoflurane preconditioning groups were significantly lower than that of the CON group (P<0.05). Isoflurane exposure before ischemia can attenuate the change of morphology of mitochondria after reperfusion. The effects of 2.0% isoflurane on reducing cytochrome c release were more remarkable than 0.5% and 1.0% concentrations of isoflurane.
Myocardioprotective effects of isoflurane preconditioning were associated with attenuation of cytochrome c loss from the inner membrane of subsarcolemmal mitochondria.
Preview · Article · Aug 2005 · Acta Pharmacologica Sinica
[Show abstract][Hide abstract]ABSTRACT: The present study was undertaken to explore the role of gamma-aminobutyric acid transporters in the neuropathic pain. On the chronic constriction injury (CCI) rats 4 doses (5, 10, 20, 40 microg in group N5, N10, N20, N40, respectively) of specific gamma-aminobutyric acid transporter-1 inhibitor NO-711 or normal saline (in group NS) were intrathecally administered before sciatic nerve ligation (pre-treatment) or at the third day after ligation (post-treatment). The paw withdrawl latency (PWL) from a noxious thermal stimulus and paw withdrawl mechanical threshold (PWMT) of von Frey filament was used as measure of thermal hyperalgesia and tactile allodynia respectively. The results demonstrated that post-treatment of NO-711 significantly suppressed thermal hyperalgesia and allodynia in CCI rats (P<0.05, P<0.01), the inhibitory effect lasted for 2 h (N40 group) and 4 h (N20 group) respectively. NO-711 inhibited thermal hyperalgesia induced by CCI in a dose-dependent manner. Intrathecal pretreatment with different doses of NO-711 delayed the occurrence of thermal hyperalgesia, but could not delay the emergence of allodynia induced by CCI. This study indicates that gamma-aminobutyric acid transporter inhibitor has anti-thermal hyperalgesia and anti-tactile allodynia effects in neuropathic rats.
[Show abstract][Hide abstract]ABSTRACT: This study was undertaken to explore the myocardioprotective effects of the combination of ischemic preconditioning (IP) with hypothermia and St.II Thomas crystalloid cardioplegic solution (CCS) on immature hearts in the rabbit. Isolated immature rabbit hearts were perfused with Krebs-Henseleit bicarbonate buffer on Langendorff apparatus. In experiment 1, 24 hearts were divided into 4 groups (n=6 in each group): Con, IP1, IP2 and IP3 group. Hearts of the four groups underwent 0, 1, 2 or 3 cycles of IP respectively. Then all the hearts were subjected to a sustained ischemia period of 2 h at 20 degrees C and a postischemic reperfusion period of 30 min at 37 degrees C. In experiment 2, 48 hearts were divided into 6 groups (n=8 in each group): SCon1, SIP1, SCon2, SIP2, SCon3 and SIP3 group, according to hypothermia and the duration of sustained ischemia (30 min at 32 degrees C; 90 min at 25 degrees C, 2 h at 20 degrees C). The SIP1, SIP2 and SIP3 groups were preconditioned twice before the sustained hypothermic ischemia, while the SCon1, SCon2 and SCon3 groups were not preconditioned. CCS was applied during sustained ischemia, all the hearts were reperfused for 30 min at 37 degrees C. Heart rate (HR), left ventricular developed pressure (LVDP) and peak rate of increase or decrease of left ventricular pressure (+/-dp/dt(max)) were recorded. Tissue concentration of adenosine triphosphate (ATP), malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) were measured. At the end of reperfusion, values of product of LVDP and HR, +/-dp/dt(max) in IP2 group were 96%+/-21%, 101%+/-19% and 84% +/-15% of the baseline values respectively, which were significantly higher than those of Con group and IP3 group (P<0.01, P<0.05); also, the ATP content of IP2 group was higher than that of the Con group (P<0.01). When CCS was applied during sustained period of hypothermic ischemia at 32 degrees C or 25 degrees C, recovery rates of RPP (rate product, =LVDPxHR) and +dp/dt(max) in SIP1 group were 87% +/-14% or 99% +/-26% of the baseline values respectively (P<0.05, vs SCon1 group), the values in SIP2 group changed to 87% +/-16% or 102% +/-20% respectively (P<0.05, vs SCon2 group). Contents of ATP in SIP1 and SIP2 groups were significantly higher than those of SCon1 or SCon2 groups respectively (P<0.05), but MDA content of the two groups were significantly lower than those of SCon1 or SCon2 groups (P<0.05) respectively. The study indicates that IP attenuates hypothermic ischemia/reperfusion injury to immature rabbit hearts under 20 degrees C ischemia, two cycles of IP showing better myocardioprotective effects than 1 or 3 cycles of IP. When IP was combined with CCS which were applied during hypothermic ischemia period, the beneficial effects of IP were weakened as the temperature during the hypothermic period was elevated.
No preview · Article · Jun 2004 · Sheng li xue bao: [Acta physiologica Sinica]
[Show abstract][Hide abstract]ABSTRACT: To study effects of ischemic preconditioning on the hypothermic ischemia/reperfusion injury of immature rabbit hearts.
The isolated immature rabbit (3-4 weeks) hearts were perfused on Langendorff apparatus. After 30 min perfusing with 37 degrees C K-H perfusate, the hearts in part one were yielded 0, 1, 2 or 3 times of IP respectively before 120 min ischemia at 20 degrees C hypothermia, and the hearts in part two were yielded 0 or 2 times of IP before being arrested by infusion of St. Thomas II crystalloid cardioplegic solution, then the arrested hearts were yielded ischemia for 30, 90 or 120 min at 32 degrees C, 25 degrees C and 2 degrees C hypothermia respectively. Then all the hearts were reperfused for 30 min at 37 degrees C normothermia. Heart rate (HR), left ventricular developed pressure (LVDP), +/- dp/dt(max) were recorded at baseline, preischemia and 1, 3, 5, 10, 20, 30 min after reperfusion. Also contents of ATP and MDA and activity of SOD and Ca(2+) -ATPase of myocardium were measured.
At the end of reperfusion, the recovery rate of left ventricular function in IP2 group were significantly higher than that of control group and IP3 group (P < 0.01, P < 0.05), also the IP2 group showed a higher content of ATP and activity of Ca(2+) -ATPase than control group and IP3 group (P < 0.01, P < 0.05). When the ischemic hearts were at different hypothermia accompanied with CCS, the recovery rate of left ventricular function and contents of ATP in SIP1 and SIP2 group were significantly higher than that of SCon 1 group and SCon 2 group respectively (P < 0.01, P < 0.05), the contents of MDA in the two IP groups were lower than that of the two control groups.
IP can attenuate the hypothermic ischemia/reperfusion injury of immature rabbit hearts, the cardioprotective effects are dependent on the mode of IP and the possible mechanisms may involve the following aspects: decrease the consumption of ATP, inhibit lipid peroxidation and maintain the activity of Ca(2+) -ATPase of cardiac myocyte.
No preview · Article · Nov 2003 · Zhongguo ying yong sheng li xue za zhi = Zhongguo yingyong shenglixue zazhi = Chinese journal of applied physiology