Ramulus Mori (Sangzhi) Alkaloids (SZ-A) Ameliorate Myocardial Injury in Type 2 Diabetic Rats by Regulating Autophagy

Abstract

Background: Diabetes mellitus (DM) is a persistent metabolic condition resulting from insufficient insulin or insulin resistance, which gives rise to diverse complications endangering human well-being. Ramulus Mori (Sangzhi) alkaloids ­(SZ-A) have various pharmacological effects, potentially benefiting clinical comprehensive kidney and cardiovascular protection. Nevertheless, the potential protective effect of SZ-A on myocardial injury in individuals with type 2 diabetes mellitus (T2DM) remains unexplored. Materials and Methods: Sprague-Dawley (SD) rats were divided into four groups, including control, model, metformin, and SZ-A. The establishment of the type 2 diabetes model was initiated by injecting streptozotocin (STZ) along with a diet of high glucose and fat. Following a 12-week period of treatment, measurements were taken for heart mass index (HMI), fasting blood glucose (FBG), and 2-h postprandial blood glucose (2hPG). Additionally, serum glycated hemoglobin (HbA1c), indicators of myocardial injury, and oxidative stress were assessed. The expressions of mammalian target of rapamycin (mTOR), p-mTOR, beclin-1, and LC3 in myocardial tissue were detected by Western blot. Results: The administration of SZ-A effectively reduced the levels of HMI, FBG, 2hPG, HbA1c, malondialdehyde (MDA), lactate dehydrogenase (LDH), and creatine kinase isoenzymes (CK-MB) in rats with type 2 diabetes while enhancing the activity of superoxide dismutase (SOD). Additionally, SZ-A could improve myocardial tissue arrangement structure and fibrosis degree. Additional analysis revealed that SZ-A suppressed the activation of p-mTOR while enhancing the levels of Beclin-1 and LC3, suggesting that the potential therapeutic impact of SZ-A on myocardial damage could be attributed to its ability to regulate autophagy, thereby mitigating oxidative stress. Conclusion: In summary, the results indicate that SZ-A might possess inhibitory properties against myocardial damage in rats with type 2 diabetes, presenting a potential therapeutic approach in the clinic.