Sheng Mai San Regulating the Oxidative Stress and Mitochondrial Damage to Alleviate Liver Injury in Heat Stress Rats

Sheng Mai San (SMS), a traditional Chinese medicine formula for treating qi and yin deficiency, is widely used in the management of conditions such as cardiovascular diseases and heatstroke. However, its role in mitigating heat stress (HS)-induced liver injury remains underexplored. In this study, a rat model of HS was established under high-temperature and high-humidity conditions, and SMS was administered as an intervention. The pharmacodynamic effects of SMS were comprehensively evaluated through histopathological examination, detection of heat shock protein 70 (HSP70) and heat shock protein 90(HSP90) expression, and analysis of liver function biomarkers (AST, ALT). Meanwhile, oxidative stress indicators were measured using biochemical assay kits (GSH, SOD, CAT, MDA, T-AOC), and transmission electron microscopy was employed to observe mitochondrial ultrastructure, thereby assessing the protective effects of SMS on hepatic oxidative stress and mitochondrial damage induced by HS. In vitro, BRL-3A cells were cultured, subjected to HS, and treated with SMS. Cell viability was assessed using the CCK-8 assay, and changes in mitochondrial reactive oxygen species (ROS) levels, mitochondrial permeability transition pore (MPTP) opening, and mitochondrial membrane potential (MMP) were evaluated using fluorescent probes. The results showed that SMS effectively restored HS-induced histopathological damage in rat liver tissues, reduced serum AST and ALT levels, and downregulated the mRNA expression of HSP70 and HSP90 in liver tissues. Meanwhile, SMS strengthened the hepatic antioxidant system by increasing the levels of GSH, SOD, T-AOC, and CAT, while decreasing MDA content. In vitro experiments confirmed that SMS increased the viability of BRL-3A cells, reduced ROS production, improved MPTP opening/closing regulation, and stabilized MMP. This study provides a clinical reference for its application in treating HS-related conditions in humans and animals.