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This Article Full Text Free Full Text (PDF) Free All Versions of this Article: 103/5/1808    most recent 00588.2007v1 Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Lee, Y.-S. Articles by Lin, V. W. Search for Related Content PubMed PubMed Citation Articles by Lee, Y.-S. Articles by Lin, V. W.

Repair of spinal cord transection and its effects on muscle mass and myosin heavy chain isoform phenotype

Departments of ¹Anatomy & Neurobiology, ²Physical Medicine & Rehabilitation, ³Orthopaedic Surgery, and ⁴Physiology & Biophysics, School of Medicine, University of California, Irvine; and ⁵Veterans Affairs Long Beach Healthcare System, Long Beach, California

Submitted 2 June 2007 ; accepted in final form 19 August 2007

A number of significant advances have been developed for treating spinal cord injury during the past two decades. The combination of peripheral nerve grafts and acidic fibroblast growth factor (hereafter referred to as PNG) has been shown to partially restore hindlimb function. However, very little is known about the effects of such treatments in restoring normal muscle phenotype. The primary goal of the current study was to test the hypothesis that PNG would completely or partially restore 1) muscle mass and muscle fiber cross-sectional area and 2) the slow myosin heavy chain phenotype of the soleus muscle. To test this hypothesis, we assigned female Sprague-Dawley rats to three groups: 1) sham control, 2) spinal cord transection (Tx), and 3) spinal cord transection plus PNG (Tx+PNG). Six months following spinal cord transection, the open-field test was performed to assess locomotor function, and then the soleus muscles were harvested and analyzed. SDS-PAGE for single muscle fiber was used to evaluate the myosin heavy chain (MHC) isoform expression pattern following the injury and treatment. Immunohistochemistry was used to identify serotonin (5-HT) fibers in the spinal cord. Compared with the Tx group, the Tx+PNG group showed 1) significantly improved Basso, Beattie, and Bresnahan scores (hindlimb locomotion test), 2) less muscle atrophy, 3) a higher percentage of slow type I fibers, and 4) 5-HT fibers distal to the lesion site. We conclude that the combined treatment of PNG is partially effective in restoring the muscle mass and slow phenotype of the soleus muscle in a T-8 spinal cord-transected rat model.

acidic fibroblast growth factor; peripheral nerve graft; spinal cord injury