The Correlation Between Autophagy Of Hippocampal Neurons And The Cognitive Impairment With Myocardial Ischemia/reperfusion In The Quinquagenarian Female Rats

Objective:Myocardial ischemia/reperfusion injury(MIRI)caused abnormal structure and funct ion of hippocampal neurons.The purpose of this study was to explore whether MIRI affected hippocampal-dependent cognitive function in the quinquagenarian female rats,and to explore the correlation between autophagy in hippocampal neurons and the cognitive impairment with MIRI in the quinquagenarian female rats.Methods:Sixty healthy female SD rats,aged 19-21 months,were randomly divided into 3 groups(n=20): control group(group C),sham operation group(group S)and ischemia reperfusion group(group IR).Before modeling,rats in 3 groups were tested in Morris Water Mase to assess their swimming speeds and the latency for 6 days.The rats in group IR were induced by 30 min occlusion of LAD follow-ed by reperfusion for 120 min with sevoflurane anesthesia.The blood samples of group IR,2 ml each,were taken before oc-clusion and after reperfusion for deter-mining the concentrations of serum cTnI.The rats in group S were received the same anesthesia and surgical procedures for 150 min,without ligating LAD.The rats in group C inhaled air/oxygen mixture for 150 min.The day after modeling,rats in 3 groups were assessed by MWM test for swimming speeds and the frequency of crossing the original platform.After the test,each rat was immediately sacrificed and its hippocampal tissues were isolated to detect the expression of Beclin1 and LC3Ⅱ by Western blot.Results:Before modeling,swimming speeds and latency in three groups have no significantly difference.After modeling,the swimming speeds of the rats in group IR still has no sig-nificantly difference,compared with group C or group S,but the frequency of crossing the original platform was decreased(P<0.05).In group IR,the levels of serum cTnI after reperfusion was significantly increased,compared with that before ischemia(P<0.05).The expressions of Beclin1 and LC3Ⅱ in hippocampal were up-regulated(P<0.05).in group IR,compared with group C or group S.the linear correlation analysis revealed that,In group IR,the expressions of LC3Ⅱ and Beclin1 in hippocampal were positively correlated with the frequency of crossing the original platform(r=0.719 and 0.688,P<0.05).Conclusion:MIRI not only induces the cognitive impairment in the quinquagenarian female rats,but also induces the activation of autophagy in hippocampal neurons.The cognitive impairment with MIRI in the quinquagenarian female rats is positively related to the upregu-lated level of autophagy in hippocampal neurons.