Therapeutic Ultrasound Decreases Mechano-Growth Factor Messenger Ribonucleic Acid Expression After Muscle Contusion Injury

McBrier NM, Lekan JM, Druhan LJ, Devor ST, Merrick MA. Therapeutic ultrasound decreased mechno-growth factor messenger ribonucleic acid expression after muscle contusion injury.ObjectiveTo examine the influence of nonthermal ultrasound on mechano-growth factor (MGF) messenger ribonucleic acid (mRNA) expression after blunt trauma.DesignA 2×4 factorial multivariate analysis of variance design.SettingUniversity research laboratory.AnimalsThirty-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.InterventionUltrasound treatment (frequency, 3MHz; intensity, 0.3W/cm2; 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.Main Outcome MeasuresMuscle mass (in grams) and MGF mRNA expression as measured via real-time reverse transcriptase polymerase chain reaction.ResultsUltrasound had no effect on muscle mass (F1,28=2.723, P=.110, 1−β=.357, η2=.089). Ultrasound treatments decreased MGF mRNA expression in the treated limb compared with the nontreated hindlimb (F1,28=6.605, P=.016, 1−β=.699, η2=.191).ConclusionsThe nonthermal ultrasound treatments resulted in decreased MGF mRNA expression after blunt trauma to the gastrocnemius muscles.