Role of Formoterol on Myogenic Regulatory Factor to Ameliorate Statin-induced Myopathy

Abstract

Objective: To investigate the effects of β2-adrenergic agonist formoterol on expression of myogenic regulatory factor myogenin in statin-induced myopathies in rats
 Methods: Adult male Sprague-Dawley rats were randomized into control (A), statin-only (B), and statin + formoterol groups (C) (n=30 per group). The control group A received no treatment. B group received simvastatin at 60 mg/kg/day by oral gavage for 12 weeks to induce myotoxicity. C group received simvastatin at 60 mg/kg/day plus formoterol at 3 μg/kg/day by oral gavage for 12 weeks. After 12 weeks, extensor digitorum longus muscles were dissected and 5 μm transverse sections were immunostained for myogenin expression. One cross section was selected from each of the specimen for study. Myogenin-positive nuclei were quantified in 8 random 40x magnification fields per muscle section by a blinded investigator. Data was analyzed using IBM SPSS.
 Results: Myogenin-positive nuclei were minimal in the control (A) group and statin-only (B) groups. In contrast, the statin + formoterol (C) group exhibited a significant increase in myogenin-positive nuclei compared to both control and statin-only groups (p<0.001), indicating enhanced muscle regeneration.
 Conclusion: Formoterol treatment augmented skeletal muscle repair pathways in a rat model of statin-induced myopathy, potentially via activation of quiescent muscle satellite cells and upregulation of myogenic regulatory factor myogenin in group C.