Myotoxic Effects of Atorvastatin Drug (Lipitor) on the Skeletal Muscles of Adult Male Albino Rats and the Effect of L- Carnitine Co-administration Light Microscopical, Immunohistochemical and Biochemical Study

Introduction: Atorvastatin (Lipitor) is a drug used for lowering serum cholesterol in cardiovascular patients. Different studies demonstrated life threatening side effects and myotoxicity of atorvastatin while others confirmed its safety. L-carnitine is a naturally occurring compound in muscular tissue and has protective effect against muscle damage. Aim of the Work: Investigation of light microscopical, immunohistochemical and biochemical changes of atorvastatin in skeletal muscles of adult male albino rat and the effect of L-carnitine co-administration. Materials and Methods: Thirty five adult male albino rats were divided into; group I (control rats), group II receiving atorvastatin and group III receiving atorvastatin and L-carnitine. After 2weeks, animals were sacrificed, creatine kinase was assisted in plasma and skeletal muscles were prepared for light microscopical study and immunohistochemical study of caspase 9 (marker for apoptosis). Results: Group I rats showed negative immune-reaction for caspase 9. Group II showed significant increase in plasma creatine kinase. Light microscopical study revealed focal areas containing split myofibers with loss of striation and dense nuclei. Excess collagen and cellular infiltration were also detected. A positive caspase 9 immune-reaction was found in affected fibers. Co-administration of L-carnitine in group III resulted in insignificant increase in creatine kinase and less light microscopical changes including cellular infiltration around few fibers with dense nuclei. Most of fibers showed negative caspase 9 immune-reaction except few positive fibers. Conclusion: Atorvastatin showed skeletal myotoxic and apoptotic changes in adult male albino rat. Co-administration of L-carnitine with atorvastatin partially prevented these changes, suggesting a possible protective effect of L-carnitine.