Effects Of Electroacupuncture At Neiguan Preconditioning On PI3K/Akt Pathway In Myocardial Tissue Of MIRI Rat

Objective: To observe the effect of electroacupuncture pre-treatment on the autophagy-related pathway phosphatidylinositol-3-kinase(PI3K)/protein kinase B(Akt)in myocardial tissue of rats with myocardial ischemia-reperfusion injury(MIRI)model,and to explore the therapeutic mechanism of electroacupuncture on MIRI.Methods:48 SD rats were randomly divided into the normal group,sham group,model group,and Neiguan group,with 12 rats in each group.The MIRI model was established by ligating the left anterior descending branch of the coronary artery.In the Neiguan group,electric acupuncture was applied to both "Neiguan" points for30 min/time,1 time/d,for 7 d.The electrocardiograms of the rats in different groups were recorded before modeling,40 min after ligation,1 min after release and 60 min after reperfusion,and the changes of ST-segment potential were analyzed.HE staining to observe pathological changes at the site of obvious myocardial injury.The expression of PI3 K and Akt in myocardial tissues of rats was observed by immunohistochemistry,and the expression levels of LC3,PI3 K,Akt and phosphorylated Akt(p-Akt)in myocardial tissues were detected by Western blotting.Results:1.Myocardial tissue morphology of rats: HE observed that myocardial tissues in the normal and sham groups were closely arranged and structurally intact,with no obvious pathological morphological changes.In the model group,the myocardial fibers were broken and disorganized,the interstitial space was widened significantly,and hemorrhage was seen in the interstitial space,with scattered inflammatory cell infiltration between myocardial fibers.A small amount of hemorrhage,myocardial fiber rupture and widening of the interstitial space were seen in the Neiguan group.2.PI3 K and Akt expression in rat myocardial tissue: The degree of PI3 K and Akt positive expression was lower in the normal group and sham group(P<0.05),while the PI3 K and Akt positive expression in the model group was higher than that in the normal group and sham group(P<0.05).The positive expression of PI3 K and Akt in myocardial tissues was decreased in the Neiguan group compared with the model group(P<0.05).3.LC3 protein expression in rat myocardial tissue: LC3-Ⅱ expression and LC3-Ⅱ/Ⅰratio were significantly higher in the model group compared with the normal and sham groups(P<0.05).LC3-Ⅱwas increased in the Neiguan group compared with the normal group(P<0.05),but there was no significant difference compared with the sham group(P>0.05).The LC3-Ⅱprotein expression level and LC3-Ⅱ/Ⅰ ratio were significantly lower in the Neiguan group than in the model group(P<0.05).4.PI3 K,Akt,p-Akt protein expression in rat myocardial tissue: There was no significant difference in the Akt protein level in each group(P>0.05).Compared with the model group,the PI3 K,p-Akt expression levels and p-Akt/Akt ratio in the normal group,sham group and Neiguan group were substantially increased(P < 0.05).Conclusion:1.Electroacupuncture Neiguan pretreatment can improve myocardial histopathology and effectively reduce myocardial tissue damage.2.Electroacupuncture Neiguan pretreatment can activate PI3K/Akt pathway in cardiomyocytes of MIRI rats,enhance PI3 K and p-Akt protein expression,reduce autophagic activity of cardiomyocytes and inhibit excessive autophagy of cells,thus exerting therapeutic effects on MIRI.