The safety evaluation of Shenze Shugan capsule and mechanism of apoptosis induced by five potentially nephrotoxic components

Abstract

Ethnopharmacological relevanceShenze Shugan capsule is a prescription of traditional Chinese medicine for nonalcoholic steatohepatitis treatment. It includes Rhei Radix et Rhizoma (RR), Cassiae Semen (CS) and Alismatis Rhizoma(AR), which widely contains rhein, emodin, aurantio-obtusin, alisol A and alisol B 23-monoacetate. Aim of the studyIn this study, we aimed to explore the safety of the medicine, and further elucidate the mechanism of apoptosis induction in HK-2 cells by five components, including rhein, emodin, aurantio-obtusin, alisol A and alisol B 23-monoacetate. Materials and methodsWe investigated the nephrotoxicity of Shenze Shugan capsule, including RR, CS, AR and mixed herbs given for two months in rats. Superoxide dismutase (SOD) in kidney tissues, urea nitrogen (BUN) and creatinine (CRE) in serum were detected, and renal pathology analysis was performed. In cell experiments, the apoptotic rate and cell cycle distribution of HK-2 cells were tested by flow cytometry. The levels of mitochondrial membrane potential (ΔΨm) and related protein expression in mitochondrial pathway were measured as well. ResultsWe confirmed that two months of administering high doses(60 times the dose for clinical use in adults) of RR, CS or mixed herbs upregulated the levels of CRE and RUN, inhibited SOD activity, and increased the degree of tubular degeneration and glomerular dilatation, but Shenze Shugan capsule has no significant differences in renal structure or renal function. In addition, we found that five components all concentration-dependently inhibited HK-2 cells proliferation and induced apoptosis, especially aurantio-obtusin as the novel nephrotoxic component. Rhein and emodin significantly induced S/M accumulation, but aurantio-obtusin, alisol A and alisol B 23-monoacetate significantly induced G1/M accumulation in HK-2 cells. Similarly, they could induce Caspase3 activation, loss of mitochondrial membrane potential (ΔΨm), and down-regulation of Bcl-2 and up-regulation of Bax. ConclusionsThrough a two-month subchronic toxicity study in rats, our preliminary determination is that this formulation is safe and reliable for long-term use. Interestingly, the potentially toxic herbs such as RR, CS, AR can reduce toxicity by drug compatibility. When further exploring the mechanism of action of toxic herbs, we found that mitochondrial pathway is involved in the apoptosis of HK -2 cells induced by rhein, emodin, aurantio-obtusin, alisol A and alisol B 23-monoacetate. Our findings provide new ideas for safety studies of Shenze Shugan capsule.