Expression of MuRF1 and MAFbx in Donor and Recipient Muscles after Musculocutaneous Nerve Transection and Partial Pectoralis Major Muscle Transfer for Reconstruction of Elbow Flexion in Rats

Abstract

. Expression of murf1 and mafbx in donor and recipient muscles after musculocutaneous nerve transection and partial pectoralis major muscle transfer for reconstruction of elbow flexion in rats. Int. J. Morphol., 33(3):975-982, 2015. SUMMARY:The expression of MuRF1 and MAFbx in a denervated muscle has previously been studied. However, the expression of MuRF1 and MAFbx in the recipient and donor muscles after muscle transfer for reconstruction of joint function has not been sufficiently investigated. Forty-two adult Sprague-Dawley rats were divided into 7 groups: normal, 1 w post-, 2 w post-, and 4 w post-musculocutaneous nerve transection; and 1 w post-, 2 w post-, and 4 w post-reconstruction of elbow flexion. Muscle wet weights were assessed, and MuRF1 and MAFbx mRNA expressions were detected by polymerase chain reaction. The length of the oblique part of the pectoralis major of an SD rat is sufficient for suture to the insertion of the biceps brachii tendon. The muscle wet weight and the wet weight retention rate of the biceps brachii continued to decline after musculocutaneous nerve transection and a gradual increase was noted after the oblique part of the pectoralis major was transferred for reconstruction of elbow flexion. The oblique part of the pectoralis major showed a decrease of only 2-6%. The upregulated expression of MuRF1 and MAFbx in the biceps brachii reached a peak 2 w after denervation and 1 w after elbow flexion reconstruction, with an increase of 15% and 4%, respectively. This was followed by downregulation; however, the expression had not normalized at postoperative 4 w. The increased expression of MuRF1 (17%) and MAFbx (1%) in the oblique part of the pectoralis major at postoperative 1 w had decreased to below normal levels at postoperative 4 w. The transfer of the oblique part of the pectoralis major for elbow flexion reconstruction after musculocutaneous nerve transection can downregulate the expression of MuRF1 and MAFbx in the recipient muscle and causes only transient damage to the donor muscle in rats.

Effect of Electroacupuncture on the Expression of Glycyl‐tRNA Synthetase and Ultrastructure Changes in Atrophied Rat Peroneus Longus Muscle Induced by Sciatic Nerve Injection Injury

“…Therefore, the study of the mechanism and the treatment of this muscle atrophy have been a popular concern. Although the mechanism study of an increase in protein degradation had achieved great progress in skeletal muscle atrophy caused by nerve injury [ 22 ], studies on the reduction of protein synthesis in muscle atrophy are poorly understood. At present, there are a lot of reports on the treatment of muscle atrophy, especially the treatment using acupuncture.…”