Abstract
Activation of muscle satellite cells (MSCs) plays a key role in muscle hypertrophy and regeneration. It is considered that MSCs are activated by muscle contraction, mechanical stretch,muscle injuries, heat-stress, etc. On the other hand,the denervation causes muscle atrophy. We hypothesized the denervation may depress MSCs activity and may delay the regenerative process of injured muscles. The purpose of this study was to investigate the effects of denervation on the regenerative process of injured skeletal muscle in mice. Male mice (C57BL/6J) were divided randomly into six groups: (1) cage control, (2) cardiotoxin (CTX)-injected (CX), (3) heat-stressed and CTX-injected, (4) denervated (DC), (5) CTX-injected and denervated (DX), and (6) CTX-injected, denervated,and heat-stressed (HDX) groups. In animals of DC, DX, and HDX groups, the denervation of hind limb muscles was performed by cutting the sciatic nerve at the gluteal region. Two weeks after the surgery, CTX was injected into tibialis anterior (TA) muscles of both limbs in CX, DX and HDX groups. TA muscles were dissected 14 and 28 days after CTX-injection. Responses of muscular protein contents and Pax7-positive muscle satellite cells during the regeneration were analyzed. Evidences suggested that heat-stress related facilitation of regeneration of injured muscle was delayed by denervation. [J Physiol Sci. 2007;57 Suppl:S94]
