Objective: To study the morphological changes of the rat claw inner skeletal muscle after ulnar nerve injury at different sections and different recovery times.
Methods: Forty-two adult male Sprague-Dawley rats were selected and placed randomly in seven groups. After establishing model of injury and repair of claw inner skeletal muscle by cutting off the ulnar nerve, the muscle wet weight, cross section area of myocytes, and collagen fibers were measured.
Results: Claw inner skeletal muscle atrophy was significantly less in experiment groups compared with the control groups after ulnar nerve injuries. The functional recovery was better in the early repair groups than the late repair group. Collagen fibers increased slowly in earlier stage, but more significantly in late stage. The muscle atrophy was similar in wrist and elbow after ulnar nerve injury during the same recovery period.
Conclusion: The function can recover completely or partly in early repair groups, but not quite effective in late stage. The increase of collagen fiber is one of the reasons to undermine the recovery effect of damaged ulnar nerve. There is no obvious difference of effect on the morphological changes of the rat claw inner skeletal muscle no matter the ulnar nerve is injured at wrist or elbow.