Therapeutic ultrasound decreases mechano-growth factor messenger ribonucleic acid expression after muscle contusion injury.

Abstract

To examine the influence of nonthermal ultrasound on mechano-growth factor (MGF) messenger ribonucleic acid (mRNA) expression after blunt trauma. A 2x4 factorial multivariate analysis of variance design. University research laboratory. Thirty-six 3- to 4-month-old male Wistar rats (mean weight, 280.8+/-21.5g). Thirty-two received a bilateral contusion injury to the gastrocnemius via a drop mass technique. Four were control animals. Ultrasound treatment (frequency, 3MHz; intensity, 0.3W/cm(2); continuous duty cycle) was started 24 hours postinjury and delivered for 5 minutes daily on 4 consecutive days. Treatment was on the left hindlimb and the contralateral right hindlimb was the nonultrasound control. Muscle mass (in grams) and MGF mRNA expression as measured via real-time reverse transcriptase polymerase chain reaction. Ultrasound had no effect on muscle mass (F(1,28)=2.723, P=.110, 1-beta=.357, eta(2)=.089). Ultrasound treatments decreased MGF mRNA expression in the treated limb compared with the nontreated hindlimb (F(1,28)=6.605, P=.016, 1-beta=.699, eta(2)=.191). The nonthermal ultrasound treatments resulted in decreased MGF mRNA expression after blunt trauma to the gastrocnemius muscles.