REHABILITATIVE INFLUENCE OF THERAPEUTIC ULTRASOUND TREATMENT ON CELLULAR MARKERS OF SKELETAL MUSCLE REGENERATION FOLLOWING BLUNT CONTUSION INJURY
Following skeletal muscle contusion injury, therapeutic ultrasound is one of the most commonly used treatment modalities among athletic trainers and other sports medicine practitioners, and is generally recognized by clinicians to be one of the most effective rehabilitative treatments for soft tissue injuries resulting from participation in sport-related physical activities. Pulsed ultrasound is characterized by a non-thermal, mechanical stimulation and, over the course of several days, this environment purportedly hastens the regenerative skeletal muscle healing process. However, the structural outcomes underlying this potential effect are poorly delineated and not well understood. Our working hypothesis was that following a blunt contusion injury to the gastrocnemius (GTN) muscle, ultrasound treatment would facilitate the recovery of several biological markers observed during the skeletal muscle regenerative repair process. Eighty male Wistar rats (3-mo) were studied. Following anesthetic administration, each animal received a bilateral contusion injury to the GTN muscle. Ultrasound treatment (pulsed, 3.3 MHz, l W/cm2, 20% duty cycle) was subsequently initiated six hours post-contusion injury unilaterally on the right (R) GTN muscle and ultrasound treatment was continued once daily for 7 days. At sacrifice, the left (non-ultrasound treated) and right (ultrasound treated) GTN muscles of 10 animals per group were excised at 1 -, 3 -, 5 -, 7 -, 14 -, 21 -, 28 -, and 40 - days post-contusion injury, trimmed of excess fat and connective tissue, and flash frozen for subsequent tissue analyses. There were no differences in muscle mass, total protein concentration, or fiber cross-sectional area (CSAf) between the right, ultrasound treated GTN muscles and the left, non-ultrasound treated GTN muscles at any time point examined. When CSAf was normalized to muscle mass, there were also no differences at any time point examined. There were no differences in myonuclear number or fiber cross-sectional area per myonuclei between the right, ultrasound treated GTN muscles or the left, non-ultrasound treated GTN muscles at any time point. The hypotheses were not supported and the results suggest that therapeutic ultrasound treatment is not effective in hastening the regeneration of skeletal muscle following a contusion injury.
School:The Ohio State University
School Location:USA - Ohio
Source Type:Master's Thesis
Keywords:skeletal muscle injury fiber cross sectional area myonuclear density
Date of Publication:01/01/2002