Decreased Expression Of Atrogin-1 In Regenerating Skeletal Muscle After Eccentric Exercise

Abstract

The muscle specific ubiquitin ligase, atrogin-1, is upregulated in many catabolic states of skeletal muscle. The role of atrogin-1 during skeletal muscle regeneration after exercise-induced muscle damage, however, has not been elucidated. PURPOSE: To evaluate the expression of atrogin-1 in regenerating skeletal muscle after eccentric exercise METHODS: Calf muscles of mice underwent forced eccentric contractionby electrical stimulation as the model of muscle damage RESULTS: Immunohistological analysis showed that muscle regeneration took place on Day 3 after exercise. After eccentric exercise, both the mRNA and protein expression of atrogin-1 remained at the control level on Day 1 and then decreased on Day 3 and 5. The level of MyoD protein, the target of atrogin-1, increased on Day 3 and 5.Figure: Caption not provided.CONCLUSIONS: These results revealed the coincidence of two events, the decrease of atrogin-1 and the increase of MyoD on Day 3 and 5 of muscle regeneration. The reduction of atrogin-1 may work as a trigger for muscle regeneration, increasing MyoD protein.