Treatment of corticosteroid-induced myopathy through Filgrastim induced endogenous stem cells mobilization in male albino rats.

Introduction: One of well-known exogenous fluorinated glucocorticoid that is used to treat inflammatory and various autoimmune illnesses is dexamethasone. Dexamethasone is known to cause skeletal muscular weakness and when used for an extended period of time, skeletal muscle undergoes atrophy. Granulocyte colony-stimulating factor (G-CSF) is a glycoprotein that helps mobilize stem cells from bone marrow into peripheral circulation. In order to maintain the function of skeletal muscle, these mobilized stem cells multiply and differentiate into mature myocytes. This study was conducted to investigate to what extent administration of filgrastim, human methionyl granulocyte colony-stimulating factor (G-CSF), ameliorates glucocorticoid-induced skeletal muscles damage in adult male albino rats.

Methods: Thirty adult male albino rats were randomly divided into three groups (ten/group), group I (control group, CG): rats received normal diet and orally given normal saline, group II (dexamethasone group, DG): rats were given dexamethasone at a dose of 0.5mg/kg for one month by intraperitoneal injection, group III (filgrastim group, FG): rats were given dexamethasone at dose of 0.5 mg/kg and on day 15, at the beginning of the third week, they were given Filgrastim at a dose of 20 µg/kg till the end of the 4th week by intraperitoneal injection with dexamethasone. Assessment of CK levels, total body weight and motor activity at different time points were done and skeletal muscles specimens were processed for light microscopy, electron microscopy and immunohistochemistry examination.

Results: Administration of dexamethasone (group II) showed variant types of pathological changes such as elevated CK, decrease in body weight, impairment of muscle activity and histologically myofibrillar disarrangement together with cellular infiltration and edema. Filgrastim group showed significant reduction in most of those manifestations. Administration of filgrastim with dexamethasone meliorated most of the symptoms related to dexamethasone induced-myopathy.

Conclusion: Filgrastim administration recovered manifestations of skeletal muscle injuries caused by dexamethasone.