The Role Of AMPK In Cerebral Ischemia-reperfusion Injury After Short-term Exercise Preconditioning In Rats

Objective: To investigate the role of AMPK in cerebral ischemia-reperfusion injury after short-term exercise preconditioning in rats,and to provide a new goal and Appropriate opportunities for intervention Method: A total of 96 clean male Wistar rats,weighing 240±20g,to be divided into randomly 8 groups,namely,exercise + sham operation group(EP+S),no exercise + sham operation group(S),12 rats in each group.Normal inactivity + t MCAO group 6 hours(S+I/R6h),12 hours(S+I/R 12h),24 hours(S+I/R 24h)exercise + t MCAO group 6 hours(EP+I/R6h),12 hours(EP+I/R)12h),24h(EP+I/R 24h)12 mice per group.The EP+S group and EP+I/R group acclimated on the electric treadmill for 3 days in advance,and then trained on the treadmill for 3 weeks.Within 1～3 hours after the last exercise,EP+I/R group was developmented t MCAO ischemia/reperfusion injury model.In EP+S group,only CCA,ECA and ICA were exposed,and the plug only entered ECA without blocking MCA.Group S and group S+I/R were fed under the same conditions,but no other intervention was given.3weeks later,the intervention measures of group S were also only exposed to CCA,ECA and ICA,and the thread plug only entered ECA without blocking MCA.Group S+I/R prepared t MCAO model.Zea-longa score was used to evaluate the degree of neurological deficit in each group.TTC staining was used to observe the infarct size of brain tissue in each group.Detected the expressions of AMPK,p-AMPK,IL-1β and TNF-α in the ischemic cortex of rats in each group by Western Blot.Results:1.Neurological function score:compared to the non-exercise group,the neurological deficit score improved in the exercise group at 6,12 and 24 h,with a statistically significant difference between 6 and 12h(P<0.05),but there was no significant difference at 24h(P>0.05).The neurological deficit score increased significantly at 12 h after CIRI compared with 6 h after CIRI in both exercise group and non-exercise group(P<0.05).The neurological deficit scores at 24 h were higher than those at 12 h,and the difference was not statistically significant(P>0.05).2.TTC staining:Compared to the non-exercise group,the cerebral infarction zone of the exercise group decreased to 6.12 and 24 h after I/R(P<0.05).In exercise group,infarct size increased at 24 h and 12 h after I/ R compared with 6h(P<0.05);Infarct size increased at 24 h after I/ R compared with 12h(P<0.05).In the no-exercise group,infarct size increased at24 h of I/ R compared with 12 h and 6h(P<0.05),and infarct size increased at 12 h after I/ R compared with 6h(P>0.05).3.Western Blot detection:Before CIRI,compared with the non-exercise group,the exercise group had a significantly higher p-AMPK/AMPK protein level and significantly lower TNF-α and IL-1β protein levels in brain tissue(P<0.05).The p-AMPK/AMPK ratio after CIRI was higher than that before CIRI in exercise group and non-exercise group,TNF-αand IL-1β were higher than those before CIRI(P<0.05).After CIRI,the p-AMPK/AMPK ratio of exercise group was higher than that of non-exercise group at 6h,12 h and 24 h of I/ R,and the levels protein of TNF-α and IL-1β in the exercise group were lower than those in non-exercise group(P<0.05).Exercise group and non-exercise group:p-AMPK increased at12 h and 24 h after CIRI compared with 6h,TNF-α and IL-1β increased(P<05).Exercise group: p-AMPK increased and TNF-α and IL-1β decreased at 24 h compared with 12h(P<0.05).p-AMPK was significantly increased and TNF-α and IL-1β were decreased at 12 h as compared with 6h(P<0.05).Sedentary group:p-AMPK increased,IL-1β decreased and TNF-α decreased at 24 h compared with 12h(P<0.05).The expression of p-AMPK is amplified and that of TNF-α and IL-1β is diminished(P < 0.05)at 12 h as compared with 6h.Conclusion:Short-term exercise preconditioning can inhibit the release of TNF-α and IL-1β after cerebral ischemia-reperfusion injury by inducing AMPK phosphorylation before t MCAO in rats.Therefore,it can reduce cerebral ischemia-reperfusion injury.