Electroacupuncture at PC 6 (nei guan) regulates cell autophagy in rats with myocardial ischemia and reperfusion*
2020, 43 (2):
Objective To observe the effect of pretreatment with electroacupuncture at PC 6 (nei guan) on cell autophagy in myocardial ischemia-reperfusion (I/R) rats, and to clarify its underlying mechanism. Methods 50 rats were randomly divided into 5 groups: sham operated group, model group, electroacupuncture pretreatment group (EA group), inhibitor pretreatment group (inhibitor group), and electroacupuncture + inhibitor pretreatment group (EA + inhibitor group) (n=10 in each group). The rats in the sham operated group were directly exposed after thoracotomy without other treatments. The rats in the model group underwent in-vivo myocardial ischemia-reperfusion. Rats in the EA group received electroacupuncture treatment on PC 6 (nei guan) 7 days prior to model establishment. Rats in the inhibitor group were injected with wortmannin (PI3K inhibitor) a week before the model was established, and received myocardial ischemia-reperfusion on the 8th day. Rats in the EA + inhibitor group received both forms of pretreatment. All rats were killed after treatment. The serum CK-MB, iNOS, and T-AOC expressions were detected by ultraviolet spectrophotometry. The expression and localization of ATG13, mTOR, and PI3K in myocardial cells were detected by immunofluorescence on paraffin sections. The pathological changes caused by cardiomyocyte autophagy in the control group were observed by HE staining experiments. Ultrastructural changes of cardiomyocytes in the control group were observed by transmission electron microscopy. Results Compared with the sham operated group, the serum CK-MB and the iNOS concentration was significantly increased, T-AOC concentrations were significantly reduced in the control group (P＜0.05). Compared with the control group, in the three pretreatment groups, the CK-MB and the iNOS concentration was decreased, T-AOC concentrations were increased (P＜0.05); among them, the effect in the EA group was the most significant. Compared with the sham operated group, the expressions of mTOR, ATG13 and PI3K in cardiomyocytes in the other four groups were all increased Compared with the model group, in the three pretreatment groups, the expression of mTOR, ATG13, and PI3K in myocardial tissues was decreased. HE staining results showed that compared with the sham operated group, in the model group, myocardial muscle fibers showed lytic rupture or even necrosis, and obvious swelling. In the three pretreatment groups, the myocardial fiber space was slightly widened, the necrotic lesions were reduced, and the myocardial cells were slightly swollen; among them the EA group showed the most obvious changes. The transmission electron microscope observation results showed that compared with the sham operated group, in the model group, the myocardial muscle fibers showed lytic rupture or even necrosis, and there were irregular and missing mitochondria. While in the three pretreatment groups, the myocardial muscle fiber gaps were slightly widened, and the nucleus and mitochondrial structure were basically complete. Among them, there was most significant change in the EA group. Conclusion Electroacupuncture pretreatment could possibly reduce myocardial I/R damage and reduce the formation of autophagosomes by promoting autophagy. While wortmannin (PI3K inhibitor) seems to reverse such a protective effect.
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