Astragaloside IV protects against autoimmune myasthenia gravis in rats via regulation of mitophagy and apoptosis.

Astragaloside IV (AS­IV) has various pharmacological effects, including antioxidant and immunoregulatory properties, which can improve myasthenia gravis (MG) symptoms. However, the potential mechanism underlying the effects of AS­IV on MG remains to be elucidated. The present study aimed to investigate whether AS­IV has a therapeutic effect on MG and its potential mechanism of action. By subcutaneously immunizing rats with R97­116 peptide, an experimental autoimmune (EA) MG rat model was established. AS­IV (40 or 80 mg/kg/day) treatment was then applied for 28 days after modeling. The results demonstrated that AS­IV significantly ameliorated the weight loss, Lennon score and pathological changes in the gastrocnemius muscle of EAMG rats compared with the model group. Additionally, the levels of acetylcholine receptor antibody (AChR­Ab) were significantly decreased, whereas mitochondrial function [ATPase and cytochrome c (Cyt­C) oxidase activities] and ultrastructure were improved in the AS­IV treated rats. Moreover, the mRNA and protein expression levels of phosphatase and tensin homolog­induced putative kinase 1, Parkin, LC3II and Bcl­2, key signaling molecules for mitophagy and apoptosis, were upregulated, whereas the mRNA and protein expression levels of p62, Cyt­C, Bax, caspase 3 and caspase 9 were downregulated following AS­IV intervention. In conclusion, AS­IV may protect against EAMG in a rat model by modulating mitophagy and apoptosis. These findings indicated the potential mechanism underlying the effects of AS­IV on MG and provided novel insights into treatment strategies for MG.