The role of mast cells in simvastatin-induced myopathy and the possible protective role of omega-3 fatty acids in adult male albino rats: light and electron microscopic study

Simvastatin is antihyperlipidemic drugs that inhibit hydroxy methylglutaryl CoA reductase to decrease cholesterol synthesis; however, it causes skeletal myopathy. Omega-3 are polyunsaturated fatty acids with anti-inflammatory and anti-oxidant effects. Mast cells have an important role in the response to tissue injury by secreting different mediators and cytokines. The current study was performed to assess the role of mast cells in simvastatin-induced myopathy and the possible protective role of omega-3 fatty acids. Forty adult male albino rats were divided into four main groups received the drugs orally for of 21 days. Group 1: 1 ml distilled water, group 2: 300 mg/kg/day omega-3, group 3: 88 mg/kg/day simvastatin, and group 4: 88 mg/kg/day simvastatin plus 300 mg/kg/day omega-3. Light and electron microscopic studies were done along with morphometric and statistical studies. Group 1 and 2 showed regular histological structure. By light microscope, group 3 revealed muscle fiber disorganization, splitting, loss of striations, and cytoplasmic fragmentation. Some nuclei were centrally displaced. Toluidine blue sections showed a large number of mast cells. By transmission electron microscope, there was loss of the regular banding pattern with irregular mitochondria, nuclei, and sarcolemma. The concurrent administration of simvastatin with omega-3 showed less myopathic changes, decrease in mast cell numbers and more activation of the satellite stem cells to accomplish the process of muscle regeneration. In conclusion, the administration of omega-3 can decrease the myopathic changes of simvastatin. Further studies are recommended to explore the mast cells' role in the progression and repair of statin-induced myopathy.