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Objective:To investigate the relationship between the mechanism of exogenous hydrogen sulfide (H 2S)-induced reduction of apoptosis in neurons during focal cerebral ischemia-reperfusion (I/R) and PINK1/Parkin pathway-mediated mitochondrial autophagy in rats. Methods:Two hundred and sixteen healthy male Sprague-Dawley rats, aged 6-8 weeks, weighing 250-270 g, were divided into 4 groups ( n=54 each) using a random number table method: control group (group C), I/R group, H 2S group and H 2S plus 3-methyladenine (3-MA) group (H 2S+ 3-MA group). Focal cerebral ischemia was induced by middle cerebral artery occlusion in anesthetized rats.In group H 2S+ 3-MA, 3-MA 10 mg/kg was intraperitoneally injected at 15 min before the onset of reperfusion, while the equal volume of normal saline was given instead in the other groups.In H 2S and H 2S+ 3-MA groups, 0.25% NaSH (a donor of exogenous H 2S) 10 mg/kg was intraperitoneally injected at the onset of reperfusion, while the equal volume of normal saline was given instead in the other groups.At 1, 3 and 7 days of reperfusion, neural function was scored, and corner test (the percentage of left turn was calculated) was performed.Brains were removed and brain tissues were obtained for determination of the cerebral infarct size, Bax, Bcl-2 and caspase-3 positive cells, cell apoptosis, and expression of mitophagy-related protein microtubule-associated protein 1 light chain 3 (LC3), PINK1 and Parkin (by Western blot). The percentage of cerebral infarct size, rate of Bax, Bcl-2 and caspase-3 positive cells and apoptosis rate were calculated.The ratio of LC3-Ⅱexpression to LC3-Ⅰexpression (LC3-Ⅱ/LC3-Ⅰ) was also calculated. Results:Compared with group C, the neural function score was significantly decreased, the percentage of left turn, percentage of cerebral infarct size, rate of Bax, Bcl-2 and caspase-3 positive cells, apoptosis rate of neurons, and LC3-Ⅱ/LC3-Ⅰ were increased, and the expression of PINK1 and Parkin was up-regulated at each time point of reperfusion in group I/R ( P<0.05). Compared with group I/R, the neural function score and rate of Bcl-2 positive cells were significantly increased, the percentage of left turn, percentage of cerebral infarct size, rate of Bax and caspase-3 positive cells, and apoptosis rate of neurons were decreased, the expression of PINK1 and Parkin was up-regulated, and LC3-Ⅱ/LC3-Ⅰ were increased at each time point of reperfusion in group H 2S ( P<0.05), and no significant change was found in the parameters mentioned above in group H 2S+ 3-MA ( P>0.05). Compared with group H 2S, the neural function score and rate of Bcl-2 positive cells were significantly decreased, the percentage of left turn, percentage of cerebral infarct size, rate of Bax and caspase-3 positive cells, and apoptosis rate of neurons were increased, the expression of PINK1 and Parkin was down-regulated, and LC3-Ⅱ/LC3-Ⅰ was decreased at each time point of reperfusion in H 2S+ 3-MA group ( P<0.05). Conclusion:The mechanism by which exogenous H 2S inhibits apoptosis in neurons during focal cerebral I/R is related to enhancing mitochondrial autophagy mediated by the PINK1/Parkin pathway in rats.
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Objective To observe the effects of remote ischaemic preconditioning on myocardium in heart operation under thoracoscope.Methods One hundred and twenty patients (72 males,48 females,aged 41-69 years,weighing 49-68 kg,falling into ASA physical status Ⅱ or Ⅲ) who received heart operation under thoracoscope were randomly divided into 2 groups (n =60 each):remote ischaemic preconditioning group (group RIPC) and control group (group C).Comparing the pH value of arterial blood around the RIPC;observing the variation of LVEF and CI at before the operation,before leaving room and 24 h after operation,and the changes of myocardial enzymes (including cTnI,CK-MB and LDH) at basic level and 6,24 and 48 h after RIPC;comparing the basic state of the two group during the perioperation.Results Compared with group C,the pH value of artery blood was lower in group RIPC after RIPC(P＜0.01).CI in RIPC group was higher than that in group C at 24 h after operation(P＜0.05);there was no statistic difference in LDH between the two groups.The value of cTnI in RIPC group was lower than that in group C at 6 and 24 h after operation (P＜0.05 or P＜0.01).The value of CK-MB in group RIPC was lower than that in group C at 6,24 and 48 h after operation (P＜0.05);there was no statistic difference in.LDH between the two groups.Basic conditions during and after the surgery in two groups had no statistic difference.Conclusion Remote ischaemic preconditioning can protect to myocardium during the heart operation under thoracoscope.
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Objective To investigated the neuroprotective effect of PTEN inhibitor BPV on cerebral ischemia-reperfusion injury in rats and its mechanism. Methods Male Sprague-Dawley rats were used to induce a reperfusion model of middle cerebral artery occlusion for 1 h. During the reperfusion, the BPV solution (0. 2 mg/kg daily) or the equal volume of saline was injected intraperitonealy immediately. The neurological deficit scores were conducted at day 1, 3,5, and 7 after ischemia-reperfusion. At day 4, triphenyl tetrazolium chloride staining was used to assess cerebral infarction volume. Enzyme-linked immunosorbent assay was used to detect the levels of interleukin 10 (IL-10) and tumor necrosis factor α(TNF-α) in cortical ischemic border zones. Real-time quantitative polymerase chain reaction was used to detect the expression level of PTEN mRNA. Western blotting was used to detect the expression levels of PI3K, Akt, and p-GSK-3β. At day 7, Bielschowsky silver staining was used to detect the axonal distribution in the ischemic border zone of the striatum. Immunohistochemical staining was used to detect the expression of myelin basic protein (MBP). Results At day 4 after ischemia-reperfusion, the infarct volume (32. 27% ± 1. 71% vs. 45. 49% ± 2. 12% ; P < 0. 001), TNF-α concentration in the cortical ischemic border zones (134. 17 ± 10. 38 pg/ml vs. 264. 17 ± 24. 84 pg/ml; P < ), and PTEN mRNA level (1. 19 ± 0. 08 vs. 2. 50 ± 0. 06; P < 0. 001) in the rats of the BPV group were al significantly lower than those of the normal saline group. The IL-10 concentration (186. 83 ± 10. 83 pg/ml vs. 147. 83 ± 11. 62 pg/ml; P < 0. 001), and the expression levels of PI3K (0. 43 ± 0. 08 vs. 0. 26 ± 0. 06; P = 0. 004), Akt (0. 52 ± 0. 05 vs. 0. 40 ± 0. 04;P = 0. 001), and p-GSK-3β (0. 75 ± 0. 08 vs. 0. 38 ± 0. 06; P < 0. 001) were al significantly higher than those of the normal saline group. At day 7 after ischemia-reperfusion, the neurological deficit score (4. 83 ± 0. 41 vs. 6. 33 ± 0. 52; P < 0. 001) in the rats of the BPV group was significantly lower than that of the normal saline group. The axon densities in the ischemic border zones (35. 51% ± 2. 45% vs. 25. 31% ± 2. 79% ; P < 0. 001) and the expression level of MBP (32. 56% ± 3. 46% vs. 27. 81% ± 4. 18% ; P = 0. 037) were significantly higher than those of the normal saline group. Conclusions BPV has neuroprotective effect for cerebral ischemia-reperfusion injury in rats. Its mechanism may be associated with the up-regulation of PTEN downstream proteins PI3K, Akt and p-GSK-3β expression to regulate inflammatory mediators and reduce the inflammatory response.
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Background Retinal ischemia/reperfusion injury is a common pathological process in ophthalmology.It can cause permanent visual impairment.The prevention and treatment of retinal ischemia/reperfusion injury is one of the focus topics at home and abroad up to now.Objective Present study was to evaluate the protective effects of geranylgeranylacetone(GGA)on retinal ischemia/reperfusion injury.Methods The retinal ischemia/reperfusion models were established in 40 SD rats by the infusion of normal saline solution into the anterior ehamber to elevate the intraoeular pressure for 1 hour and then remove the process.GGA of 2 ml (800 ms/kg)was intragastrieally administered in 20 model rats as GGA group,and the equal volume of normal saline solution was used at the same way in other 20 models as model group.Four normal matched SD rats were served as normal control group.The histological changes of retina in 6,24,48,72 hours after modeling was examined by hematoxylin-eosin staining under the light microscope.and the expression of heat shock protein 70(HSP70)and caspase-3 in retina at the time points mentioned above was detected by immunohistochemistry.Results The edema of cornea and retina of rats appeared in 1 hour and peaked in 24 hours after modeling.In 72 hours after modeling,the edema was alleviated but the disorder of retina structure was found in model group.However,although the pathological change process was similar to that of model group,the damage of retina tissue was milder in the rats of GGA group under the light microscope.HSP70 and caspase-3 were absent in the retina of normal rats.But。The expression of HSP70 in retinal ganglion cells(RGCs)was found in 6 hours after modeling,reached peak in 24 hours and declined after that in model group.The numbers of positive cells for HSP70 in retina was significantly increased in various time points in GGA group,showing statistically significant differences between model group and GGA group(P<0.05).In model group,a few of caspase-3 positive cells were found 6 hours after reperfusion and increased gradually until reaching the peak 24 hours and then decreased gradually 48 hours later.Few caspase-3 positive cells were found 72 hour8 after reperfusion.The numbers of positive cells for caspase-3 decreased in GGA group compared with model group during the experimental duration with the considerable difference between these two groups(P<0.05).Conclusion GGA could protect RGCs against isehemia/reperfusion injury by upregulating the expression of HSP70 and downregulating the expression of caspase-3 in retina.
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Objective To investigate the protective effect of losartan on acute ischemia-reperfusion(I/R)(injury) of pancreas in rats.Methods Seventy-two Wister rats were randomly divided into 3 groups:(1)(Control group);(2)Ischemia-reperfusion group:the anterior mesenteric artery and the celiac artery were(occluded) for 15 min,30min and 60min followed by 6 hours reperfusion;(3)Losartan group:losartan(40mg/kg)were administered by gavage at 12h and 1h before arterial occlusion.The pathologic changes of pancreatic tissue were observed under light microscopy;TUNEL was used to detect apoptosic of pancreatic cells;Bcl-2 expression in the pancreatic cells of rats was analyzed by immunohistochemistry technique.(Results) Losartan treatment reversed the histological abnormalities including infiltration of inflammatory cells and atrophy of acinar cells.Compared with losartan group,pancreatic tissue of I/R group exhibited increased MDA[((20.1?1.2))nmol/g and((34.9?2.6)) vs(17.9?2.1)nmol/g and(25.2?3.3)nmol/g,P
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Objective:To observe the effects of prolonged transient acidosis on cardiac hemodynamics in aged rat heart after reperfusion injury.Methods:60 isolated SD rats hearts(≥18 months)perfused by Langendorff were randomly divided into 6 groups(n=10):(1)normal contro1(C)group;(2)reperfusion injury(I/R)group;(3)ischemic postconditioning(IPO)group;(4)acidosis(H+)group;(5)postconditioning+alkalotic(IPO+OH-)group;(6)alkalotic(OH-)group.The direct effects of prolonged transient acidosis on myocardiac contractility were observed by a langendorff apparatus through the hemodynamics parameters including heart rate(HR),left ventricular systolic pressure(LVSP),left ventricular end-diastolic pressure(LVEDP),and ?dp/dtmax.Results:The LVEDP were increased and HR,LVSP,?dp/dtmax were decreased in I/R group,IPO group,H+ group,IPO+OH-group and OH-group compared with those in C group(P