[Effect of moxibustion on cardiac function and expression of autophagy-related proteins of cardiomyocytes in chronic heart failure rats].

Objective: To observe the effect of moxibustion on cardiac function and expression of myocardial tumor suppressor protein p53, mammalian target of rapamycin (mTOR) and phosphorylated(p)-mTOR (excessive autophagy-associated proteins of cardiomyocytes) in rats with chronic heart failure (CHF), so as to explore its mechanisms underlying improvement of CHF.

Methods: SD rats were divided into blank control (＝11), model(＝8), autophagy activator (＝8), autophagy inhibitor (＝9) and moxibustion(＝9) groups. The CHF model was established by i．p. injection of Doxorubicin Hydrochloride (DOX, 1 mg/mL, 1-4 mg/kg) every other day. Moxibustion was applied to bilateral "Feishu" (BL13) and "Xinshu" (BL15) for 20 min, 5 times a week for 3 weeks. Rats of the autophagy activator group received gavage of Rapamycin (RAPA, 2 mg/kg) and those of the autophagy inhibitor group received i．p. injection of Methyladenine (3-MA, 15 mg/kg) 5 times a week for 3 weeks after successful modeling. The heart weight and body weight were measured to calculate heart mass index (HW/BW＝heart weight ÷ body weight). Cardiac output (CO) and heart rate (HR) were measured by using a cardiac function meter. Serum N-terminal pro-brain natriuretic peptide (NT-pro BNP) content was assayed by using ELISA, and the expression of myocardial p53, p-mTOR and mTOR proteins was examined by Western blot.

Results: (1) Compared with the blank control group, the HR, HW/BW, NT-pro BNP content and p53 expression levels were significantly increased (<0.01), and the CO and ratio of p-mTOR/mTOR were significantly decreased in the model group (<0.01). (2) Compared with the model group, the HR, HW/BW and NT-pro BNP content of the autophagy inhibitor and moxibustion groups were significantly decreased (<0.01, <0.05), and CO and p-mTOR/mTOR ratio were significantly increased in both autophagy inhibitor and moxibustion groups (<0.01). (3) Compared with the autophagy activator group, the levels of HR, HW/BW, NT-pro BNP and p53 in the autophagy inhibitor and moxibustion groups were significantly lower (<0.01), and those of CO and p-mTOR/mTOR levels were significantly higher (<0.01).

Conclusion: Moxibustion, similar to the autophagy inhibitor, has a protective action on myocardium in CHF rats, which is possible by preventing over expression of myocardial autophagy-associated proteins during CHF.