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AIM: To examined the effects of hypoxic preconditioning ( HPC) on oxygen-glucose deprivation ( OGD)-induced PC12 cells, and to investigate its possible mechanisms of autophagy .METHODS: Cultured PC12 cells were randomly divided into control group , HPC group, 3-methyladenine (3-MA) group, HPC+OGD group, 3-MA+HPC+OGD group and OGD group .CCK-8 assay was used to detect the cell viability .The caspase-3 activity was also tested . TUNEL staining and flow cytometry were used to detect the cell apoptosis .The protein levels of apoptosis-related protein caspase-3 and autophagy-marked protein LC3-2 and beclin-1 were determined by Western blot .RESULTS:Compared with control group, the viability of PC12 cells was significantly reduced , and the activity of caspase-3 was significantly increased in OGD group.Compared with 3-MA+HPC+OGD group and OGD group , the viability of PC12 cells was significantly in-creased, and the activity of caspase-3 was significantly reduced in HPC +OGD group (P<0.05).The PC12 cell injury was apparent after OGD with a great increase in the apoptotic rate (P<0.05).Compared with OGD group, the apoptotic rate significantly decreased in HPC +OGD group ( P<0.05 ) .Compared with control group , the protein level of cleaved caspase-3 was significantly increased in OGD group ( P<0.05) .Compared with OGD group , the protein level of cleaved caspase-3 was significantly decreased , and the levels of LC3-2 and beclin-1 were significantly increased in HPC +OGD group (P<0.05).CONCLUSION:OGD decreases cell survival and induces apoptosis .Activation of cell autophagy may be the mechanism by which hypoxic preconditioning protects the PC 12 cells from OGD induced injury .
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Objective To study the role of adiponectin (ADP)post-conditioning in alleviating myocardial ischemia reperfusion injury (MIRI) in 3-week old rats.Methods SD rats (3-week old) were randomly divided into 4 groups by random digits table (n =6):sham group was processed identically except that the left anterior descending coronary artery(LAD) was not ligated;MIRI group was subjected to occlusion of the LAD followed by reperfusion,occlusion for 30 min and reperfusion for 120 min;ADP group was subjected to injection of ADP into femoral vein before reperfusion;LY294002 group (ADP post-conditioning and LY294002) was subjected to injection of ADP and LY294002 into femoral vein before reperfusion.The titer of lactate dehydrogenase(LDH),cardiac troponin I(cTnl) and malondialdehyde(MDA) in plasma were observed.The levels of superoxide dismutase (SOD)and MDA in myocardial tissue were observed.Results The levels of LDH,cTnI and MDA in plasma of MIRI group was (732.11 ± 111.29) IU/L,(38.05 ± 6.17) g/L and (4.49 ± 0.17) nmol/L,respectively,compared with sham group,the levels of LDH,cTnI and MDA in plasma of MIRI group increased obviously(all P ＜ 0.05);the levels of LDH,cTnI and MDA in plasma of ADP group were (581.72 ± 68.41) IU/L,(20.70 ± 5.43) g/L and (3.10 ± 0.20) nmol/L,respectively;compared with MIRI group,the levels of LDH,cTnⅠ and MDA in plasma of ADP group declined significantly (all P ＜0.05);the levels of LDH,cTnI and MDA in plasma of LY294002 group were (701.10 ±99.59) IU/L,(33.13 ± 4.32) g/L and (4.19 ± 0.46) nmol/L,compared with ADP group,the levels of LDH,cTnI and MDA in plasma of group LY294002 increased remarkably (t =2.477,1.804,2.961,all P ＜ 0.05).Compared with sham group,the SOD level decreased and the MDA level increased in myocardial tissue of MIRI group(all P ＜ 0.05);compared with MIRI group,the SOD level increased and the MDA level decreased in myocardial tissue of ADP group (all P ＜ 0.05);compared with ADP group,the SOD level decreased and the MDA level increased in myocardial tissue of LY294002 group (all P ＜ 0.05).Conclusions ADP postconditioning is perhaps a protective factor for alleviating myocardial ischemia reperfusion injury in 3-week-old rats,the protective effect is perherps related to alleviating the damage of the lipid peroxidation by signaling pathway of adiponectin/phosphoinositide-3 kinase/protein kinase B.
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[ABSTRACT]AIM:ToexaminetheeffectsofhighconcentrationofextracellularATPonhumanneuroblastoma SH-SY5Y cell injury.METHODS: Cultured SH-SY5Y cells were grouped according to the concentrations of ATP and treatment time.The cell viability was detected by CCK-8 assay.The variation of autophagic vacuoles was observed with monodansylcadaverine staining .The cell apoptosis was analyzed by Hoechst 33258 staining.Meanwhile, apoptotic rate was detected by flow cytometry .The levels of caspase-3 and microtubule-associated protein 1 light chain 3-Ⅱ ( LC3-Ⅱ) were determined by Western blotting .RESULTS:Compared with control group , the survival rate of SH-SY5Y cells was signifi-cantly reduced by ATP at different concentrations (3, 6, 9, 12 and 15 mmol/L for 3 h) and different treatment time (1, 2, 3 and 6 h with 6 mmol/L ATP, peaking at 3 h).The autophagic vacuoles of SH-SY5Y cells were significantly increased at 1 h with ATP treatment , trended to decrease over time and returned to control level at 6 h.The protein expression of LC3-Ⅱwas significantly increased at 1 h with ATP treatment , which was consistent with the time points of increasing auto-phagic vacuoles .LC3-Ⅱexpression level gradually decreased at 2~3 h with ATP treatment , and returned to control level at 6 h.Compared with control group , the apoptotic rate and the expression level of caspase-3 were enhanced synchronously . The peak of apoptotic rate occurred at 3 h, and kept until 6 h.The level of cleaved caspase-3 expression peaked at 6 h. CONCLUSION:High concentration of extracellular ATP induces the autophagy and apoptosis of SH -SY5Y cells.The in-creased autophagy shows up , followed by the climax of apoptosis until 6 h.With the prolonged duration of ATP , apoptosis is the main process in the cells .
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Objective To explore the expression of Hes1 mRNA during neural stem cells(NSC) differentiation toward neurons . Methods To establish the model of cultivation NSC in the hippocampal of newborn (24 h) SD rats ,and then to observe the mor-phology of NSC in the course of proliferation and differentiation .Before and after cellular induction ,the expression of Nestin and NSE were respectively measured to detect cell types by immunochemistry method .And flow cytometry was used to determine cell cycle phases ,so as to detect proliferative activity of these cells .Meanwhile ,the expression of Hes1 mRNA in NSC was determined by reverse transcription-PCR(RT-PCR) .Results The results demonstrated that NSC isolated from hippocampal showed vigorously clonal proliferation in vitro ,and positive Nestin expression .In addition ,the differentiated cells demonstrated positive NSE expres-sion .Flow cytometry analysis showed that the percentage of NSC in S phase was obviously higher than that of induced differentia-tion of all time(P0 .05) .Conclusion The high level of Hes1 mRNA was probably involved proliferation of NSC .How-ever ,low level of Hes1 mRNA might contribute to neuronal differentiation .