Effect Of IGF-Ⅰon Regeneration Of SD Rat Skeletal Muscle After Motility Damage

Background The training effect lies on the equilibrium of the two facets. Presently, the domestic study of skeletal muscle exercise damage is rarely done which is mainly localized in the study of exercise effect to the ultrastructure, bio-chemistry and enzymology in the skeletal muscle. Overseas study of cell factors expression in exercise-induced skeletal muscle damage is in the initial phase.The regeneration of skeletal muscle which is followed by complicated biological regulative mechanism is relative to many cell factors. Thereinto the cell factor insulin-like growth factor(IGF) is concerned with cell proliferation and differentiation in the rehabilitation for skeletal muscle damage. IGF-I chiefly promotes the cell proliferation of skeletal muscle, while IGF-II is vital in the differentication of the proliferated skeletal muscle cells. Otherwise, basic fibroblast growth factor (bFGF) is the primary growth factor in the regulation of skeletal muscle embryogenesis, growth and development which is potent regulator in skeletal muscle proliferation and differentiation. Cell apoptosis is an important factor in the cell necrose following the skeletal muscle damage. The apoptosis relative genes such as Bcl-2, Bax are crucial in skeletal muscle cell spoptosis.Adaptation and damage are two dichotomal facets in daily physical exercise and military training.Objective To study the effect of IGF-I on the regeneration of satellite cells after sports injury, and explore the applications of IGF-Iin the field of repairof skeletal muscle after sports injury.Methods Using SD rat 1 week exhausting model, on 1,3,5th day after the first exhausting,300mg/lml IGF-I was injected into the middle of right gastrocnemius muscle of the treatment group. The control groups were injected 1ml saline. The samples were taken on the 7,9,11,17,24,30th days after the first exhausting, the skeletal muscle was dyed with HE and observed with optical microscope and electric microscope. The expression of proliferating cell nuclear antigen (PCNA) in it were compared. Results On the 7,11,17th days after the first exhausting, the satellite cells decreased significantly in the treatment group, the collagen fibres increased in the control groups. On the 30th day, the muscle fibre's shape was in good condition for the treatment groups, but healed with scar tissue in the control groups. Observed by electric microscope, the biolast's shape is normal, new born muscle fibre can be found in the treatment groups, expanded sarcoplasmic reticulum, increased glycogen granule, engorged biolast and apoptotic cells can be found in the control groups. The PCNA exponent of the treatment group was obviously higher than the control group.Conclusions IGF-I can accelerate the regeneration of skeletal muscle satellite cells after sports injury.