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Objective To evaluate the effect of electroacupuncture (EA) preconditioning on inositol-requiring kinase 1 (IRE1)-X-box binding protein 1 (XBP1) signaling pathway in endoplasmic reticulum in the cortex in a rat model of cerebral ischemia-reperfusion (I/R).Methods One hundred and eight pathogen-free healthy male Sprague-Dawley rats,aged 8-12 weeks,weighing 200-250 g,were assigned into 3 groups (n =36 each) using a random number table:sham operation group (group S),group I/R and EA preconditioning group (group EA).Focal cerebral I/R was induced by occlusion of right middle cerebral arteries for 2 h followed by reperfusion in rats anesthetized with chloral hydrate.In group EA,Baihui acupoints were stimulated with an electric stimulator for 30 min once a day for 5 consecutive days starting from 5 days before ischemia,and the model was established at 24 h after the last preconditioning.Rats were sacrificed after neurological deficit was scored at 6,12 and 24 h of reperfusion,brains were removed,and the ischemic area in cerebral cortex was isolated for examination of the cell ultrastructure (with an electronic microscope) and for determination of the expression of IRE1 and XBP1 (by Western blot).Results Compared with group S,the neurological deficit scores were significantly increased,and the expression of IRE1 and XBP1 in the ischemic area was up-regulated at each time point in I/R and EA groups (P＜0.01).Compared with group I/R,the neurological deficit scores were significantly decreased,and the expression of IRE1 and XBP1 was up-regulated at each time point in group EA (P＜0.05).The cell damage in the ischemic area in cerebral cortex was significantly attenuated in group EA when compared with group I/R.Conclusion The mechanism by which EA preconditioning attenuates cerebral I/R injury is related to activating IRE1-XBP 1 signaling pathway and relieving endoplasmic reticulum stress in rats.
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Objective To evaluate the effect of electroacupuncture (EA) preconditioning on the activity of dynamin-related protein 1 (Drp1) in brain tissues during cerebral ischemia-reperfusion (I/R) in rats.Methods A total of 126 pathogen-free healthy adult male Wistar rats,weighing 250-300 g,were divided into 3 groups (n =42 each) using a random number table:sham operation group (group S),group I/R and EA preconditioning group (group EA).In group S,the blood vessels were only separated but not occluded.In group I/R,a nylon thread with rounded tip was inserted into the left middle cerebral artery advanced cranially until resistance was met,and middle cerebral artery occlusion was maintained for 2 h followed by reperfusion.In group EA,Baihui acupoints were stimulated with an electric stimulator (2/ 15 Hz disperse-dense waves,intensity 1 mA) for 30 min,lasting for 5 consecutive days,and the model of focal cerebral I/R was established at 24 h after the last stimulation.At 6,24 and 48 h of reperfusion,the neurologic deficit was assessed and scored,the mitochondria in the cerebral cortex on the ischemic side were extracted,the expression of Drpl in mitochondria was detected using Western blot,the mitochondrial uhrastructure was examined with an electron microscope,and neuroapoptosis was measured using TUNEL.The apoptosis rate was calculated.Results Compared with group S,the neurological deficit score and apoptosis rate were significantly increased,and the expression of Drpl in mitochondria was up-regulated at each time point in I/R and EA groups (P＜0.05).Compared with group I/R,the neurological deficit score and apoptosis rate were significantly decreased,and the expression of Drpl in mitochondria was down-regulated at each time point in group EA (P＜0.05).Conclusion The mechanism by which EA preconditioning reduces cerebral I/R injury may be related to inhibiting the activity of Drpl and thus inhibiting the excessive fission of mitochondria in rats.
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Objective To evaluate the effect of dexmedetomidine on the mammalian target of rapamycin(mTOR)/tau protein signaling pathway in the hippocampus of aged rats after splenectomy.Methods One hundred and fifty pathogen-free healthy male Sprague-Dawley rats,aged 18 months,weighing 400-540 g,were divided into 5 groups(n=30 each)using a random number table:control group(group C),sham operation group(group S),operation group(group O),normal saline group(group NS)and dexmedetomidine group(group D).Group C received no treatment.Ten percent chloral hydrate 0.3 ml/100 g was injected intraperitoneally in group S.Group O underwent splenectomy.Dexmedetomidine 50 μg/kg was injected intraperitoneally at 5 min before splenectomy in group D.The equal volume of normal saline was injected intraperitoneally at 5 min before splenectomy in group NS.Morris water maze test was performed at day 7 after surgery.At days 1,3 and 7 after surgery,the rats were sacrificed,and the hippocampi were removed for examination of the pathological changes in the hippocampal CA3 region and for determination of the expression of mTOR protein and mRNA,tau protein mRNA and phosphor-tau protein(pS396 tau protein)(by real-time polymerase chain reaction or Western blot).Results Compared with group C,the escape latency and swimming distance were significantly prolonged,and the expression of mTOR protein and mRNA,tau protein mRNA and pS396 tau protein was up-regulated in O,D and NS groups(P0.05).Compared with group O,the escape latency and swimming distance were significantly shortened,and the expression of mTOR protein and mRNA,tau protein mRNA and pS396 tau protein was down-regulated in group D(P0.05).The pathological changes in the hippocampal CA3 region were significantly attenuated in group D as compared with group O.Conclusion The mechanism by which dexmedetomidine improves postoperative cognitive function may be associated with inhibited activation of mTOR/tau protein signaling pathway in the hippocampus of aged rats.
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Intraportal transplantation of islets is no longer considered to be an ideal procedure and finding the extrahepatic alternative site is becoming a subject of high priority. Herein, in this study, we would introduce our initial outcomes of using gastric submucosa (GS) and liver as sites of islet autotransplantation in pancreatectomized diabetic Beagles. Total pancreatectomy was performed in Beagles and then their own islets extracted from the excised pancreas were transplanted into GS (GS group, n=8) or intrahepatic via portal vein (PV group, n=5). Forty-eight hours post transplantation, graft containing tissue harvested from the recipients revealed the presence of insulin-positive cells. All recipients in GS group achieved euglycemia within 1 day, but returned to a diabetic state at 6 to 8 days post-transplantation (mean survival time, 7.16±0.69 days). However, all of the animals kept normoglycemic until 85 to 155 days post-transplantation in PV group (mean survival time, 120±28.58 days; P<0.01 vs. GS group). The results of intravenous glucose tolerance test (IVGTT) confirmed that the marked improvement in glycometabolism was obtained in intrahepatic islet autotransplantation. Thus, our findings indicate that the liver is still superior to the GS as the site of islet transplantation, at least in our islet autotransplant model in pancreatectomized diabetic Beagles.
Subject(s)
Animals , Dogs , Humans , Diabetes Mellitus, Experimental , Metabolism , Pathology , Therapeutics , Gastric Mucosa , Metabolism , Transplantation , Glucose , Metabolism , Glucose Tolerance Test , Graft Survival , Insulin , Metabolism , Islets of Langerhans Transplantation , Liver , Pathology , Liver Transplantation , Transplantation, AutologousABSTRACT
<p><b>OBJECTIVE</b>To modify the isolation and culture method of Sertoli cells and investigate its' effects on xeno-lymphocytes apoptosis.</p><p><b>METHODS</b>Sertoli cells which was isolated from 2 - 4 week-old Sprague Dawley (SD) rats, were successfully prepared by collagenase type V, trypsin and DNase I and then identified by electron microscope. Viability and apoptosis of cultured cells were measured by flow cytometry. The apoptosis rates of Balb/c mouse lymphocytes were examined which were co-cultured with Sertoli cells of SD rats by flow cytometry, too. The expression of FasL, TGF-beta(1) and clusterin on Sertoli cells were detected by immunocytochemistry.</p><p><b>RESULTS</b>In the co-cultured system, Sertoli cells accounted for more than 90%. The viability of Sertoli cells was above 95% and the apoptosis rate was 10.87% +/- 3.87% in this study. The lymphocytes apoptosis ratio was 15.52% +/- 0.17% (P < 0.01). Streptavidin-biotin-peroxidase-complex immunochemistry staining showed that the Sertoli cells could express FasL, TGF-beta(1) and clusterin, respectively.</p><p><b>CONCLUSIONS</b>It indicates that the expression of FasL, TGF-beta(1) on the Sertoli cells might relate to the immune privilege, and it supposed to be benefit for xenotransplantation.</p>