engleski

Myogenin expression in rat skeletal muscles

Introduction: Transcriptional myogenic factors are expressed during process of denervation or regeneration in adult skeletal muscles. The family of basic helix-loop-helix (bHLH) regulatory factors consists of MyoD, Myf-5, myogenin and MRF4. MyoD, Myf-5 and MRF4 can act as myogenic determination factors, directing progenitor cells into myogenic program. Myogenin, MRF4 and MyoD can control myogenic cell differentiation which is characterized by activation of muscle genes and formation of muscle fiber. The aim of this study was to investigate expression of myogenin during the process of muscle regeneration in fast and slow skeletal muscles. Material and methods: In 2- month-old Wistar rats, the regeneration process was induced in both type of muscles, slow (m.soleus, SOL) and fast (m. tibialis anterior, TA) by injection of 1 ml of local anesthetic bupivacaine and transection of the sciatic nerve near head of the femur. Immunohistochemical and Western blot analysis were performed for detection of myogenin in SOL and TA muscles. Results: Immunohistochemical analysis of TA and SOL muscles during the process of regeneration demonstrated that both myonuclei and satellite cells were myogenin positive. Western blot analysis showed a significant upregulation of myogenin protein in TA and SOL muscles in first 14 days, and protein expression could not be detected after that period. Conclusions: In adult skeletal muscle myogenin is expressed as satellite cells begin to differentiate. Myogenin, a key regulator of myogenesis, controls muscle atrophy upon denervation and also has role during muscle regeneration.

Muscle regeneration; Myogenin; Rat; Western blot

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