[Effect and mechanism of Shenmai Injection in regulating copper death in myocardial fibrosis in rats].

Based on copper death, this study investigates the effect and mechanism of Shenmai Injection on isoproterenol(ISO)-induced myocardial fibrosis(MF) in rats. SPF-grade male SD rats were randomly divided into a normal group, model group, captopril(5 mg·kg~(-1)) positive control group, and Shenmai Injection low(6 mL·kg~(-1)), medium(9 mL·kg~(-1)), and high(12 mL·kg~(-1)) dose groups. Except for the normal group, the rats in the other groups were subcutaneously injected with ISO(5 mg·kg~(-1)) once a day for 10 consecutive days to establish an MF model. Starting from the second day after successful modeling, intraperitoneal injections of the respective treatments were administered for 28 consecutive days. Hematoxylin-eosin(HE) and Masson staining were used to observe pathological changes and fibrosis levels in the myocardial tissue. Colorimetry was employed to detect serum Cu~(2+) concentration in rats. The levels of inflammatory cytokines interleukin-6(IL-6), interleukin-1β(IL-1β), interleukin-18(IL-18), tumor necrosis factor-α(TNF-α), as well as mitochondrial energy metabolites adenosine triphosphate(ATP), adenosine diphosphate(ADP), and adenosine monophosphate(AMP) in serum were measured using enzyme-linked immunosorbent assay(ELISA). Western blot was performed to detect the expression of collagen Ⅰ(Col-Ⅰ), collagen Ⅲ(Col-Ⅲ), and copper death-related proteins dihydrolipoamide acetyltransferase(DLAT), ferredoxin 1(FDX1), lipoic acid synthetase(LIAS), and heat shock protein 70(HSP70) in myocardial tissue. Immunofluorescence was used to detect the expression of DLAT, FDX1, and HSP70, while immunohistochemistry was conducted to examine the expressions of DLAT, FDX1, LIAS, and HSP70. The results showed that, compared to the model group, the myocardial structure disorder and collagen fiber deposition in the drug treatment groups were significantly improved, the cardiac index level was reduced, serum Cu~(2+), IL-6, IL-1β, IL-18, TNF-α, ADP, and AMP levels were significantly decreased, ATP levels were significantly increased, and the expressions of Col-Ⅰ, Col-Ⅲ, and HSP70 proteins in myocardial tissue were significantly reduced, while the expressions of DLAT, FDX1, and LIAS proteins were significantly elevated. In conclusion, Shenmai Injection effectively alleviates myocardial structure disorder and interstitial collagen fiber deposition in ISO-induced MF rats, promotes copper excretion, and reduces copper death in the ISO-induced rat MF model.