Effects of Recombinant Mechano-Dependent Growth Factor on the Background of Chronic Alcoholization in Rats

Physical loading or mechanical injury to muscles causes the product of the insulin-like growth factor 1 (IGF-1) gene to undergo alternative splicing, leading to production of a splice variant termed mechano-dependent growth factor (MGF). Previous in vitro experiments have demonstrated increases in the proliferative activity of myogenic precursors on exposure to MGF. However, the question of the physiological effects of MGF in the structures of normal and pathologically altered skeletal muscle remained open. We report here studies of the effects of administration of recombinant full-size MGF into the gastrocnemius muscle of rats during at 30-day recovery period after 16 weeks of alcohol intoxication. Alcoholized rats showed significant decreases in the intensity of proliferation of satellite cells, decreases in the numbers of myonuclei, and decreases in the phosphorylation of p90RSK. Studies of the level of phosphorylation of ribosomal S6 protein kinase p70S6K indicated that there were no significant changes. Administration of MGF increased the proliferative activity of myogenic precursors and restored the pool of myonuclei; the level of phosphorylation of p90RSK was also increased.