title: Therapeutic ultrasound decreases mechano-growth factor messenger ribonucleic acid expression after muscle contusion injury.
abstract: OBJECTIVE
  To examine the influence of nonthermal ultrasound on mechano-growth factor (MGF) messenger ribonucleic acid (mRNA) expression after blunt trauma.
  
  
  METHODS
  A 2x4 factorial multivariate analysis of variance design.
  
  
  METHODS
  University research laboratory.
  
  
  METHODS
  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.
  
  
  METHODS
  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.
  
  
  METHODS
  Muscle mass (in grams) and MGF mRNA expression as measured via real-time reverse transcriptase polymerase chain reaction.
  
  
  RESULTS
  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).
  
  
  CONCLUSIONS
  The nonthermal ultrasound treatments resulted in decreased MGF mRNA expression after blunt trauma to the gastrocnemius muscles.
authors.affiliation: Department of Kinesiology, Pennsylvania State University, University Park, PA 16802, USA. nmm13@psu.edu
authors.forename: Nicole M
authors.initials: NM
authors.lastname: McBrier
authors.forename: Jaimy M
authors.initials: JM
authors.lastname: Lekan
authors.forename: Lawrence J
authors.initials: LJ
authors.lastname: Druhan
authors.forename: Steven T
authors.initials: ST
authors.lastname: Devor
authors.forename: Mark A
authors.initials: MA
authors.lastname: Merrick
mesh_terms: D000818:Animals; D003288:Contusions / Q000378:metabolism / Q000628:therapy*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D018482:Muscle, Skeletal / Q000293:injuries / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D014464:Ultrasonic Therapy
chemical_list: D012333:RNA, Messenger; C519382:mechano-growth factor, rat; D007334:Insulin-Like Growth Factor I