[Show abstract][Hide abstract] ABSTRACT: We investigated the effects of a cell-permeable superoxide dismutase mimetic, manganese(III) tetrakis(1-methyl-4-pyridyl)porphyrin (MnTMPyP) on blood-brain barrier (BBB) integrity following pentylenetetrazole (PTZ)-induced seizures in experimental preeclampsia symptoms induced by N(omega)-nitro-L-arginine methyl ester (L-NAME) in pregnant rats. To show the functional and morphological alterations in BBB integrity, quantitative analysis of sodium fluorescein (NaFlu) extravasation, immunohistochemistry and electron microscopic assessment of horseradish peroxidase (HRP) permeability were performed. Varying degrees of proteinuria were seen and arterial blood pressure increased in L-NAME-treated pregnant rats (p<0.01). MnTMPyP pretreatment and convulsive PTZ challenge significantly decreased the immunoreactivity of occludin in hippocampal capillaries in L-NAME-treated pregnant rats (p<0.01). BBB permeability to NaFlu significantly increased in pregnant rats treated with L-NAME plus PTZ (p<0.01), but MnTMPyP pretreatment did not significantly decrease NaFlu penetration into the brain parenchyma in these animals. Ultrastructurally, frequent vesicles containing HRP reaction products were observed in the capillary endothelial cells in the cerebral cortex and hippocampus of pregnant rats treated with L-NAME and L-NAME plus PTZ with the abundance being more in the latter group. MnTMPyP pretreatment caused a marked reduction in the frequency of HRP reaction product containing vesicles in both experimental settings. In conclusion, the results of the present study provide evidence that MnTMPyP plays an important role in limiting the enhanced vesicle-mediated transcellular transport in BBB endothelium in a rat model of preeclampsia and the differences in the way of transports of NaFlu and HRP might be responsible for the different effects of MnTMPyP on the BBB permeability to these two tracers.
Brain research 05/2014; 1563. DOI:10.1016/j.brainres.2014.03.029 · 2.84 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Hyperbaric oxygen (HBO) treatment yields conflicting results on blood-brain barrier (BBB) integrity under various pathological conditions and the effects of HBO on healthy brain is poorly understood. In this experimental study, the effects of HBO on BBB integrity were investigated in comparison with hyperbaric air (HBA) in intact rats. Four sessions of HBA or HBO were applied to intact rats in 24h. BBB integrity was functionally and structurally evaluated by determining extravasation of Evans blue (EB) dye and horseradish peroxidase (HRP) tracers. In immunohistochemical evaluation, relative staining intensity for occludin, a tight junction (TJ) protein, and aquaporin 4 (AQP4), a water-channel protein, was detected in the barrier type of microvessels of brain by image analysis. BBB permeability to EB dye significantly increased in animals in HBO treatment group compared to those in HBA and control groups (p<0.05). The immunoreactivity of occludin, a tight junction protein, remained essentially unaltered in capillaries of hippocampus in all groups. In animals exposed to HBO, AQP4 immunoreactivity significantly increased in parietal cortex compared to those in HBA and control groups (p<0.01). Ultrastructurally, frequent vesicles containing HRP reaction products were observed in capillary endothelial cells in cerebral cortex and hippocampus of rats subjected to both HBA and HBO. Our results indicate that the HBO administration to intact rats increased BBB permeability to both EB and HRP while HBA increased only HRP extravasation in these animals. The results of this study suggest that HBA also impairs the BBB integrity in intact rats as well as HBO.
Brain research 08/2013; 1531. DOI:10.1016/j.brainres.2013.07.052 · 2.84 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Aims:
This study investigates the effects of vagus nerve stimulation (VNS) on seizure severity and blood-brain barrier (BBB) integrity in kindled rats with cortical dysplasia (CD).
Pregnant rats were exposed to 145 cGy of gamma-irradiation on day 17 of pregnancy. In offsprings, kindling was induced by giving subconvulsive doses of pentylenetetrazole. Left VNS was performed for 48 h at output currents of 0.5 or 1 mA. Horseradish peroxidase (HRP) was used to study the BBB permeability. Immunohistochemistry for occludin and P-glycoprotein (P-gp) was also performed.
Kindled rats with CD exhibited seizures with mean Racine's scores of 3.57 ± 1.2 during video EEG recording. Kindled animals with CD receiving VNS at 0.5 and 1.0 mA did not exhibit either clinical or electrophysiological signs of seizure. Immunostaining for occludin, a tight junction protein, in hippocampus remained relatively intact in all groups. VNS-treated and -untreated kindled animals with CD revealed intense immunostaining for P-gp in hippocampal formation (P<0.01). Electron microscopic observations revealed frequent transport vesicles containing electron-dense HRP reaction products in the cytoplasm of brain capillary endothelial cells in both cerebral cortex and hippocampus of kindled animals with CD. Those which were exposed to 1 mA VNS were observed to have brain capillary endothelial cells largely devoid of HRP reaction products in both cerebral cortex and hippocampus.
The results of this study suggest that VNS therapy at 1 mA inhibits seizure activity and protects BBB integrity by limiting the enhancement of transcellular pathway in kindled animals with CD.
Life sciences 01/2013; 92(4-5). DOI:10.1016/j.lfs.2013.01.009 · 2.70 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We investigated the effects of topiramate (TPM), a novel broad spectrum anticonvulsant, on seizure severity, survival rate and blood-brain barrier (BBB) integrity during hyperthermic seizures in rats with cortical dysplasia (CD). Offsprings of irradiated mothers were used in this study. To show the functional and morphological alterations in BBB integrity, quantitative analysis of Evans blue (EB) extravasation, immunohistochemistry and electron microscopic assessment of horseradish peroxidase (HRP) permeability were performed. Rats with CD exposed to hyperthermia exhibited seizures with mean Racine's scores of 3.92±1.2. Among the rats with CD pretreated with TPM, 21 of 24 rats showed no sign of seizure activity upon exposure to hyperthermia (p<0.01). The immunoreactivity of occludin, a tight junction protein, remained essentially unaltered in capillaries of hippocampus in all groups. In animals with CD exposed to hyperthermia, the significantly increased p-glycoprotein immunoreactivity in hippocampus (p<0.01) was slightly decreased by TPM pretreatment. Hyperthermic seizures increased BBB permeability to EB in animals with CD, but TPM pretreatment decreased the penetration of the tracer into the brain in these animals (p<0.01). Ultrastructurally frequent vesicles containing HRP reaction products were observed in capillary endothelial cells in cerebral cortex and hippocampus of rats with CD subjected to hyperthermia-induced seizures, and TPM pretreatment prevented the development of HRP reaction products in these animals. The results of this study suggest that TPM inhibits seizure activity and maintains BBB integrity in the course of febrile seizures in the setting of CD.
Brain research 11/2012; 1494. DOI:10.1016/j.brainres.2012.11.039 · 2.84 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The effects of immunoglobulin G and immunoglobulins enriched with immunoglobulin A and immunoglobulin M on blood-brain barrier integrity and survival rates in septic rats were comparatively investigated.
Sepsis was induced by cecal ligation and perforation in Sprague-Dawley rats. The animals were divided into the following groups: Sham, cecal ligation and perforation, cecal ligation and perforation plus immunoglobulin G (250 mg/kg, intravenous), and cecal ligation and perforation plus immunoglobulins enriched with immunoglobulin A and immunoglobulin M (250 mg/kg, intravenous). Immunoglobulins were administered 5 mins before cecal ligation and perforation and the animals were observed for behavioral changes for 24 hrs following cecal ligation and perforation. Blood-brain barrier permeability was functionally and structurally evaluated by determining the extravasation of Evans Blue and horseradish peroxidase tracers, respectively. Immunohistochemistry and Western blotting for occludin were performed.
The high mortality rate (34%) noted in the septic rats was decreased to 15% and 3% by immunoglobulin G and immunoglobulins enriched with immunoglobulin A and immunoglobulin M, respectively (p < .01). Both immunoglobulin G and immunoglobulins enriched with immunoglobulin A and immunoglobulin M alleviated the symptoms of sickness behavior in the septic rats, with the animals becoming healthy and active. Increased extravasation of Evans Blue into the brain tissue of the septic rats was markedly decreased with the administration of both immunoglobulin G and immunoglobulins enriched with immunoglobulin A and immunoglobulin M (p < .01). Occludin expression remained essentially unchanged in all groups, including the cecal ligation and perforation group. In the cecal ligation and perforation group, increased luminal and abluminal vesicles containing electron-dense horseradish peroxidase-reaction product were noted in the cytoplasm of endothelial cells located in the hippocampus and the cerebral cortex. Tight junction was ultrastructurally intact, suggesting that the transcellular pathway is responsible for the blood-brain barrier breakdown in sepsis. Following immunoglobulin G or immunoglobulins enriched with immunoglobulin A and immunoglobulin M treatment, no ultrastructural evidence of leaky capillaries in the brain was observed in the septic rats, indicating the blockade of the transcellular pathway by immunoglobulins administration.
Our study suggests that immunoglobulin G and immunoglobulins enriched with immunoglobulin A and immunoglobulin M improve the integrity of the blood-brain barrier and inhibits cecal ligation and perforation-induced symptoms of sickness behavior in rats.
Critical care medicine 12/2011; 40(4):1214-20. DOI:10.1097/CCM.0b013e31823779ca · 6.31 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The mechanisms underlying the changes in blood-brain barrier (BBB) integrity in septic encephalopathy are poorly understood. The present study was designed to examine whether hyperbaric oxygen therapy (HBOT) influences the response of BBB to sepsis induced by cecal ligation and puncture (CLP) in rats. Cerebral cortical and hippocampal tissue levels of tumor necrosis factor-alpha (TNF-α), malondialdehyde (MDA) and glutathione (GSH) levels were measured. BBB permeability was functionally and structurally evaluated by determining extravasation of Evans blue (EB) and horseradish peroxidase (HRP) tracers, respectively. Immunohistochemistry and western blotting for occludin were performed. HBOT did not alter TNF-α levels in CLP operated rats while a significant decrease was noted when the therapy was subjected to intact rats. MDA levels in animals subjected to CLP plus HBOT were significantly decreased. In septic rats, the decreased GSH levels were significantly increased by HBOT. While HBOT attenuated the increased BBB permeability to EB in rats subjected to CLP (P<0.01), no macroscopic alteration was observed in the enhanced HRP extravasation. An increase in HRP extravasation was also observed by HBOT in intact animals. Occludin immunoreactivity and expression remained essentially unchanged in the brain capillaries of animals in all groups. Ultrastructurally, frequent vesicles containing HRP reaction products were observed in brain capillary endothelial cells of animals treated with CLP and/or HBOT. In conclusion, our results revealed that HBOT did not provide overall protective effects on the BBB integrity in septic conditions and even led to BBB disruption in intact animals.
Brain research 09/2011; 1412:63-72. DOI:10.1016/j.brainres.2011.07.020 · 2.84 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Blood-brain barrier (BBB) constituted primarily by the capillary endothelial cells functions to maintain a constant environment for the brain, by preventing or slowing down the passage of a variety of blood-borne substances, such as serum proteins, chemical compounds, ions, and hormones from the circulation into the brain parenchyma. Various diseases such as brain tumors, epilepsy, and sepsis disturb the BBB integrity leading to enhanced permeability of brain microvessels. In animal models, a variety of experimental insults targeted to the BBB integrity have been shown to increase BBB permeability causing enhanced passage of molecules into the brain paranchyma by transcellular and/or paracellular pathways. This alteration can be demonstrated by intravascular infusion of exogenous tracers and subsequent detection of extravasated molecules in the brain tissue. A number of exogenous BBB tracers are available, and they can be used for functional and structural analysis of BBB permeability. In this chapter, we aimed to highlight the basic knowledge on the use of three most commonly performed tracers, namely Evans blue dye, sodium fluorescein, and horseradish peroxidase. The experimental methodologies that we use in our laboratory for the detection of these tracers by macroscopy, spectrophotometry, spectrophotofluorometry, and electron microscopy are also discussed. While tracing studies at the morphological level are mainly aimed at the identification and characterization of the tracers both in the barrier related cells and brain parenchyma, spectrophotometric and spectrophotofluorometric assays enable quantification of BBB permeability. The results of our studies that we performed using the mentioned tracers indicate that barrier type of endothelial cells in brain play an important role in paracellular and/or transcytoplasmic trafficking of macromolecules across BBB under various experimental settings, which may provide new insights in both designing approaches for the management of diseases with BBB breakdown and developing novel trans-BBB drug delivery strategies.
[Show abstract][Hide abstract] ABSTRACT: The mechanisms underlying the changes in blood-brain barrier (BBB) integrity and the generation of seizures in childhood associated with preexisting brain lesions like cortical dysplasia (CD) are poorly understood. We investigated the effects of levetiracetam (LEV) on BBB integrity and the survival during hyperthermic seizures in rats with CD.
Pregnant rats were exposed to 145 cGy of gamma-irradiation on embryonic day 17. On postnatal day 28, hyperthermia-induced seizures were evoked in offspring with CD. To show the functional and morphological alterations in BBB integrity, quantitative analysis of sodium fluorescein (NaFlu) extravasation, immunohistochemistry and electron microscopy were performed.
Seizure scores and mortality rates were decreased by LEV during hyperthermia-induced seizures in rats with CD (P<0.01). Increased NaFlu extravasation into brain by hyperthermia-induced seizures in animals with CD was decreased by LEV (P<0.01). While glial fibrillary acidic protein (GFAP) immunoreactivity slightly increased in brain sections of animals with CD during hyperthermia-induced seizures, LEV led to GFAP immunoreactivity comparable to that of controls. Decreased occludin immunoreactivity and expression in CD plus hyperthermia-induced seizures was increased by LEV. Opening of tight junctions and abundance of pinocytotic vesicles representing ultrastructural evidences of BBB impairment and severe perivascular edema were observed in animals with CD exposed to hyperthermia-induced seizures and LEV treatment led to the attenuation of these findings.
These results indicate that LEV may present a novel approach for the protection of the BBB besides its antiepileptic impact on hyperthermic seizures in the setting of CD.
Life sciences 09/2010; 87(19-22):609-19. DOI:10.1016/j.lfs.2010.09.014 · 2.70 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Chronic suppurative otitis media causes some disturbance to the chorda tympani nerve (CTN), which may affect the facial nerve. It is not possible to perform a biopsy of the main truncus of the facial nerve, therefore studies of the CTN might show possible pathologic or physiologic changes of the facial nerve in the future.
The specific aim of this study was to investigate the effects of chronic suppurative otitis media on the CTN.
The tympanic segments of CTNs were collected for ultrastructural investigations in patients with chronic suppurative otitis media who underwent canal wall-down tympanoplasty. The study population comprised 10 patients, 7 males, 3 females; the age range was 16-66 years, and the mean age was 38. Qualitative and semiquantitative evaluations were performed on the specimens of CTN by electron microscopy.
Our histopathologic examinations showed that there were changes of varying severity in all the CTNs such as scarcity of unmyelinated nerve fibers, Schwann cell nucleus condensation, scarcity of Schwann cell cytoplasm, adaxonal vacuolation and edema, myelin sheath disintegration, shrunken electron-dense axoplasm, increased collagen fibers, adaxonal circular lamellar complex, interstitial edema, and vacuolation of Schwann cell cytoplasm.
[Show abstract][Hide abstract] ABSTRACT: Non-alcoholic fatty liver disease has long been accepted as benign; however, recent evidence suggests that the disease may progress to cirrhosis and hepatocellular carcinoma, although the natural course of the disease is still unclear. This study was designed to comparatively evaluate electron microscopic features of non-alcoholic fatty liver (NAFL) and non-alcoholic steatohepatitis (NASH).
Quantitative and semi-quantitative ultrastructural evaluations were performed on liver biopsies from 23 patients, 10 with NAFL and 13 with NASH.
No statistically significant difference was noted between NAFL and NASH patients in ultrastructural features of hepatocytes including megamitochondria, intramitochondrial crystalline inclusions, mitochondrial matrix granules, foamy cytoplasmic appearance, electron-lucent and glycogen-containing nuclear regions, lipofuscin granules, or an increased frequency of vesicles containing electron-dense material in peribiliary Golgi zone; however, the mitochondrial diameter was significantly higher in the NASH patients. Intercellular distance and microvilli between hepatocytes, collagen and electron-dense material accumulation in the space of Disse, electron-dense material accumulation and microvillus density in bile canaliculi did not differ significantly between the groups.
Our data show that, although NAFL and NASH can be distinguished by their distinct light microscopic features, ultrastructural characteristics are similar, which suggests that NAFL may also have the potential to progress to fibrosis and cirrhosis like NASH.
Journal of Gastroenterology and Hepatology 03/2010; 25(3):619-26. DOI:10.1111/j.1440-1746.2009.06142.x · 3.50 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This study investigates the effects of levetiracetam (LEV) on the functional and structural properties of blood-brain barrier (BBB) in pentylenetetrazole (PTZ)-kindled rats with cortical dysplasia (CD). Pregnant rats were exposed to 145 cGy of gamma-irradiation on embryonic day 17. In offsprings, kindling was induced by giving subconvulsive doses of PTZ three times per week for 45 days. While all kindled rats with CD died during epileptic seizures evoked by the administration of a convulsive dose of PTZ in 15 to 25 min, one week LEV (80 mg/kg) pretreatment decreased the mortality to 38% in the same setting. LEV caused a remarkable decrease (p<0.01) in extravasation of sodium fluorescein dye into the brain tissue of kindled animals with CD treated with convulsive dose of PTZ. Occludin immunoreactivity and expression remained essentially unchanged in all groups. Immunoreactivity for glial fibrillary acidic protein (GFAP) was observed to be slightly increased by acute convulsive challenge in kindled rats with CD while LEV pretreatment led to GFAP immunoreactivity comparable to that of controls. An increased c-fos immunoreactivity in kindled rats with CD exposed to convulsive PTZ challenge was also observed with LEV pretreatment. Tight junctions were ultrastructurally intact, whereas LEV decreased the increased pinocytotic activity in brain endothelium of kindled rats with CD treated with convulsive dose of PTZ. The present study showed that LEV decreased the increased BBB permeability considerably by diminishing vesicular transport in epileptic seizures induced by convulsive PTZ challenge in kindled animals with CD.
Brain research 05/2009; 1281:71-83. DOI:10.1016/j.brainres.2009.05.033 · 2.84 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Objective: Tinea pedis is the most common superficial fungal infection of the foot. Although light microscopic characteristics of tinea pedis have already been described and are well known, electron microscopic data is still lacking. In this study, we aimed to examine the ultrastructural changes in the epidermis of patients diagnosed with tinea pedis. Material and Methods: Biopsies were taken from the lesions between the toes of patients with untreated tinea pedis and from healthy volunteers with no fungal infections. The materials obtained were prepared for electron microscopy and examined by transmission electron microscope. Results: The ultrastructural examination revealed the following changes: (1) Disturbances in the form and organization of keratinocytes; (2) Irregular distribution and interlacing of tonofilament bundles in keratinocytes; (3) Disruption of desmosomes and detachment of adjoining keratinocytes; (4) Excessive widening of intercellular spaces between keratinocytes; (5) Dilatation of intercellular spaces between basal cells; (6) Degranulation of melanocytes in the stratum basale; (7) Migration of lymphocytes and polymorphonuclear leukocytes between keratinocytes in the stratum spinosum; (8) Degradation of basal lamina; (9) Pericapillary edema in the apillary dermis. Conclusion: The ultrastructural findings in tinea pedis are described and related to the clinical symptoms and histopathologic features of the disease.
Medical Journal of Trakya University / Trakya Universitesi Tip Fakultesi Dergisi 01/2009; 28(2). DOI:10.5174/tutfd.2009.03515.3 · 0.11 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A 31-year-old woman who presented with photophobia was found to have bilateral corneal and conjunctival crystal deposition. Ocular cystinosis was diagnosed upon observation of typical crystals and lack of systemic involvement. In vivo confocal microscopy confirmed crystal deposition of the corneas and conjunctivae bilaterally. Optical coherence tomography showed stromal hyper-reflectivity due to crystals within the corneal stroma. Transmission electron microscopy of the conjunctiva demonstrated pathognomonic intralysosomal cystine crystals inside fibroblasts and macrophages. Clinicopathological characteristics of ocular cystinosis are well described by this exceptional case.
[Show abstract][Hide abstract] ABSTRACT: Cortical dysplasia (CD) is one of the major causes contributing to epileptogenesis associated with blood-brain-barrier (BBB) disturbances. The current study investigated the functional and ultrastructural changes of BBB in pentylenetetrazole (PTZ)-kindled rats with CD. Pregnant rats on E17 were exposed to 145 cGy of gamma-irradiation and offspring were used for experiments. The rats were given PTZ three times per week to induce kindling. The permeability of BBB was determined by using sodium fluorescein (NaFlu). Immunohistochemistry for occludin, GFAP and c-fos, western-blot analysis for occludin and electron microscopy for the ultrastructural alterations in BBB were performed. The brain level of NaFlu did not increase in rats with CD and/or kindling. Following administration of a convulsive dose of PTZ, a significant increase in BBB permeability was observed in kindled rats with CD. Occludin immunoreactivity and expression remained essentially unchanged in all groups. Slightly enhanced immunoreactivity for GFAP was observed in all groups except control. c-fos immunoreactivity in brain sections of kindled rats with CD displayed a striking increase by convulsive PTZ challenge. Tight junctions were ultrastructurally intact, whereas markedly increased number of pinocytotic vesicles was noted in brain endothelium of kindled rats with CD by convulsive dose of PTZ. The present study showed that epileptic seizures induced by convulsive PTZ challenge during kindling-mediated epileptogenesis in the presence of CD changed both functional and ultrastructural properties of the BBB and considerably enhanced transendothelial vesicular transport, while paracellular pathway was apparently not involved in this setting.
Brain Research 06/2008; 1208:181-91. DOI:10.1016/j.brainres.2008.02.101 · 2.84 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Distraction osteogenesis is a well established clinical treatment for limb length discrepancy and skeletal deformities. Transforming growth factor beta 1 (TGF-beta1) is a multifunctional peptide which controls proliferation and expression of cells specific to bone like chondrocytes, osteoblasts, osteoclasts including mesenchymal precursor cells. To decrease the external fixation time with increasing the strength of regenerate (newly formed bone after distraction) we tested the effect of locally applied transforming growth factor beta 1 on distraction osteogenesis. A total of 28 mature female white New zealand rabbits weighing 3,5 kg-4,5 kg were studied. 10 animals were belonging to biomechanical testing group (5 for the study and 5 for the control subgroups), and the others were to histology group. In biomechanical group after tibial osteotomy TGF-beta1 was applied subperiosteally for 5 days just proximal to osteotomy site. Control group received only the solvent. Seven days after tibial osteotomy distraction was started at a rate of 0.25 mm/12 hours for 3 weeks with a unilateral fixator. Rabbits were sacrificed at the end of a consolidation period 8 week after tibial osteotomy. We assessed density of the elongation zone of rabbit tibial bones with the computed tomography. Then biomechanical parametres were assessed using the torsional testing using the material testing machine. In histology group rabbits were classified as control and study (rabbits that were given TGF-beta1). Rabbits were sacrificed at the end of first week, second week and fourth week also at the end of consolidation period 8 week after tibial osteotomy. Immunohistochemical and histologic parameters were examined. Biomechanical testing was applied as torsional testing. These values are used in determination of maximal loading, stiffness and energy absorbed during testing (brittleness). The histomorphometric examination looked for the differences between the study and control groups in terms of bone formation pattern, bone quality and quantity. The immunohistochemical studies investigated the mechanism of TGF-beta1, and its presence in different cell types. The results of this study suggest that locally applied TGF-beta1 improves the mineral density of distraction gap and load to failure(energy absorbed during testing). Though there is no significant histomorphometric difference between the study and control groups, there is an increased bone mineral density and an according maximum energy absorbance in the study group. This effect can be explained by the following mechanism: TGF-beta1 exerts its effect on two different receptor types (Type 1 and 2). Type 1 receptors are localized to bone matrix and type 2 receptors are localized to the intracellular space. The specific stains utilized in the current experiment are specific to type 2 receptors. They have been shown to be down-regulated by exogenous TGF-beta1 injections. Most probably, type 1 receptors are up-regulated by this exogenous administration, but unfortunately, there is currently no specific stain on tha market to display type 1 receptors and to prove this explanation.
[Show abstract][Hide abstract] ABSTRACT: We investigated the effects of lipopolysachharide (LPS) on functional and structural properties of the blood-brain barrier (BBB) during pentylenetetrazole (PTZ)-induced epileptic seizures in rats. Arterial blood pressure was significantly elevated during epileptic seizures irrespective of LPS pretreatment. Plasma levels of interleukin (IL)-1, interleukin (IL)-6, nitric oxide (NO) and malondialdehyde (MDA) increased while catalase concentrations decreased in animals treated with LPS, PTZ and LPS plus PTZ. The significantly increased BBB permeability to Evans blue (EB) dye in the cerebral cortex, diencephalon and cerebellum regions of rats by PTZ-induced seizures was markedly reduced upon LPS pretreatment. Immunoreactivity for tight junction proteins, zonula occludens-1 and occludin, did not change in brain vessels of animals treated with PTZ and LPS plus PTZ. Glial fibrillary acidic protein immunoreactivity was increased in LPS, but not in PTZ and LPS plus PTZ. These results indicate that LPS pretreatment reduces the passage of EB dye bound to albumin into the brain, at least partly, by increasing plasma NO and IL-6 levels during PTZ-induced epileptic seizures. We suggest that LPS may provide protective effects on the BBB integrity during epileptic seizures through transcellular pathway, since the paracellular route remained unaffected by LPS and LPS plus PTZ.
Life Sciences 06/2006; 79(1):1-7. DOI:10.1016/j.lfs.2005.12.035 · 2.70 Impact Factor