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Objective:To evaluate the role of acetaldehyde dehydrogenase 2 (ALDH2) in hippocampus in memory decline after myocardial ischemia-reperfusion (I/R) in rats.Methods:Twenty-four healthy male Sprague-Dawley rats, aged 2-3 months, weighing 220-280 g, were divided into 3 groups ( n=8 each) using a random number table method: sham operation group (group S), myocardial I/R group (group I/R) and ALDH2 agonist ALDA-1 group (group ALDA-1). Myocardial I/R was induced by 30 min occlusion of left anterior descending branch of coronary artery followed by 120 min reperfusion in anesthetized animals.ALDA-1 10 mg/kg was intraperitoneally injected at 5 min before ischemia in group ALDA-1.The positioning navigation training in Morris water maze test was started from 6 days before developing the model.The spatial exploration in Morris water maze test was performed at 24 h after developing the model.The rats were sacrificed after the end of behavioral experiment, and the hippocampus was extracted for microscopic examination of the pathological changes (by hematoxylin and eosin staining) and for determination of the apoptosis index (AI) (by TUNEL staining), activity of ALDH2 (by colorimetry), contents of 4-hydroxynonenal (4-HNE) and malondialdehyde (MDA) (by enzyme-linked immunosorbent assay), and expression of ALDH2 and 4-HNE (by Western blot). Results:Compared with group S, the number of crossing the original platform was significantly decreased, the time spent in the target quadrant was shortened, the activity of ALDH2 in the hippocampus was decreased, the expression of 4-HNE was up-regulated, and the contents of 4-HNE and MDA and AI were increased in group I/R ( P<0.05). Compared with group I/R, the number of crossing the original platform was significantly increased, the time spent in the target quadrant was prolonged, the ALDH2 activity was increased, the expression of 4-HNE was down-regulated, and the contents of 4-HNE and MDA and AI were decreased in group ALDA-1 ( P<0.05). There was no significant difference in ALDH2 expression in hippocampus among the three groups ( P>0.05). Conclusions:The mechanism of memory decline developed after myocardial I/R may be related to the decrease in ALDH2 activity and promotion of accumulation of aldehydes in the hippocampus of rats.
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Objective To evaluate the relationship between the failed mechanism of sevoflurane postconditioning-induced myocardial protection and the activity of dynamin-related protein 1(Drp1)in dia-betic rats. Methods Pathogen-free healthy adult male Sprague-Dawley rats, weighing 220-280 g, in which diabetes mellitus was induced by combination of high-fat and high-sucrose diet and intraperitoneal injection of streptozotoein 30 mg∕kg, were studied.Sixty rats with diabetes mellitus were divided into 5 groups(n=12 each)using a random number table: sham operation group(group Sham), myocardial ischemia∕reperfusion (I∕R)group(group I∕R), sevoflurane postconditioning group(group SP), Drp1 inhibitor mitochondrial division inhibitor-1(Mdivi-1)group(group M)and Mdivi-1 plus sevoflurane postconditioning group(group M-SP). Myocardial I∕R was induced by occluding the left anterior descending branch of the coronary artery for 30 min followed by 120 min reperfusion except for group Sham. Mdivi-1 1.2 mg∕kg was intraperito-neally injected at 15 min before ischemia in M and M-SP groups, and 2.5% sevoflurane was inhaled starting from 5 min of reperfusion in SP and M-SP groups. Blood samples were collected from the right internal jugular vein at 120 min of reperfusion for measurement of serum cardiac troponin I(cTnI)concentrations(by en-zyme-linked immunosorbent assay). Rats were then sacrificed and myocardial specimens were obtained for de-termination of the myocardial infarct size(by TTC), cell apoptosis(by TUNEL), expression of Bax, Bcl-2 and activated caspase-3(by Western blot)and nicotinamide adenine dinucleotide(NAD+)content(by spectrophotometry). Apoptosis index(AI)and Bax∕Bcl-2 ratio were calculated. Results Compared with group Sham, the percentage of myocardial infarct size, serum concentration of cTnI, AI and Bax∕Bcl-2 ratio were significantly increased, the expression of activated caspase-3 was up-regulated, and the NAD+content was decreased in the other four groups(P<0.05). Compared with group I∕R, the percentage of myocardial infarct size, serum concentration of cTnI, AI and Bax∕Bcl-2 ratio were significantly decreased, the expres-sion of activated caspase-3 was down-regulated, and the NAD+content was increased in group M-SP(P<0.05), and no significant change was found in the parameters mentioned above in SP and M groups(P>0.05). Compared with group SP, the percentage of myocardial infarct size, serum concentration of cTnI, AI and Bax∕Bcl-2 ratio were significantly decreased, the expression of activated caspase-3 was down-regulated, and the NAD+content was decreased in group M-SP(P<0.05), and no significant change was found in the parameters mentioned above in group M(P>0.05). ConclusionThe failed mechanism of sevoflurane postconditioning-induced myocardial protection may be related to the activity of Drp1 in diabetic rats.
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Objective To investigate the effect of inhibition of glycogen synthase kinase?3 beta ( GSK?3β) activity on sevoflurane postconditioning?induced cardioprotection in diabetic rats. Methods Healthy adult male Sprague?Dawley rats, weighing 250-300 g, in which diabetes mellitus was induced by intraperitoneal 1% streptozotocin 60 mg∕kg combined with high?fat and high?sucrose diet and confirmed by blood glucose level >16. 7 mmol∕L. Forty rats with diabetes mellitus were divided into 5 groups ( n=8 each) using a random number table: sham operation group ( S group ) , ischemia?reperfusion ( I∕R ) group, sevoflurane postconditioning group ( SP group) , GSK?3β inhibitor SB216763 group ( SB group) , and sevoflurane postconditioning plus SB216763 group ( SS group ) . Myocardial ischemia was induced by 30 min occlusion of the left anterior descending branch of the coronary artery followed by 120 min reperfu? sion. The rats inhaled sevoflurane with the end?tidal concentration of 2.5% for 5 min starting from 1 min be?fore reperfusion in group SP. SB216763 0.2 mg∕kg was injected via the caudal vein at 1 min before reperfu?sion in group SB. In group SS, the rats inhaled sevoflurane with the end?tidal concentration of 2.5% for 5 min starting from 1 min before reperfusion, and SB216763 0.2 mg∕kg was injected via the caudal vein at 1 min before reperfusion. At 120 min of reperfusion, blood samples were collected from the carotid artery for determination of serum creatine kinase?MB (CK?MB) activity and cardiac troponin I (cTnI) concentra?tions. Myocardial specimens were collected at 120 min of reperfusion for microscopic examination of the pathological changes and for determination of myocardial infarct size ( by 2,3,5?triphenyltetrazolium chlo?ride staining) and phosphorylated GSK?3β (p?GSK?3β) expression (by Western blot). Results Com?pared with group S, the myocardial infarct size and serum CK?MB activity and cTnI concentration were sig?nificantly increased, and the expression of p?GSK?3βwas significantly down?regulated in I∕R, SP, SB and SS groups (P0.05) . Compared with group SB, the myocardial infarct size and serum CK?MB activity and cTnI concentration were significantly decreased, and the expression of p?GSK?3β was sig?nificantly up?regulated in group SS (P<0.05). The pathological changes of myocardium were significantly attenuated in SB and SS groups as compared with group I∕R and group SP . Conclusion Inhibition of GSK?3β activity can improve sevoflurane postconditioning?induced cardioprotection in diabetic rats.
