title: Aerobic exercise affects myostatin expression in aged rat skeletal muscles: a possibility of antiaging effects of aerobic exercise related with pelvic floor muscle and urethral rhabdosphincter.
abstract: OBJECTIVE
  Aging-induced loss of muscle mass and subsequent reduction of strength is a fundamental cause of frailty, functional decline, and disability. And this may lead to muscular dysfunction, voiding dysfunction, or urinary incontinence due to pelvic muscle weakness induced by aging. Physical exercise has been recommended for the prevention and the treatment of these age-related frail states. We investigated the effects of treadmill exercise on muscle strength, myostatin mRNA and protein expression, and gastrocnemius myocytes proliferation in aged rats to investigate the possible antiaging effects of aerobic exercise on skeletal muscles such as pelvic floor muscles and urethral rhabdosphincter muscle.
  
  
  METHODS
  In this study, 5-month-old male Sprague-Dawley rats were used as the young-age group (n=20) and 24-month-old rats were used as the old-age group (n=20). Each group was randomly divided into two groups (n=10 in each group): the sedentary and the treadmill exercise group. The rats in the exercise groups were forced to run on a motorized treadmill for 30 minutes, once a day, for 6 weeks. For this study, a weight load test, hematoxylin and eosin staining, real-time and reverse transcription polymerase chain reaction for myostatin mRNA, myostatin western blot, and 5-bromo-2'-deoxyuridine immunohistochemistry were performed in the gastrocnemius muscle.
  
  
  RESULTS
  The age-induced reduction of muscle mass and strength was associated with a decrease in myocyte proliferation and an increase in myostatin mRNA and protein expression in the gastrocnemius. However, treadmill exercise improved muscle mass and strength through suppression of myostatin mRNA and protein expression, and myocyte proliferation increase in the gastrocnemius against the aging process.
  
  
  CONCLUSIONS
  Aerobic exercise is a useful strategy for enhancing muscle function against aging-induced loss of skeletal muscle mass and functions.
authors.affiliation: Department of Physiology, Kyung Hee University School of Medicine, Seoul, Korea. ; Department of Exercise Physiology ∙ Prescription, Graduate School of Health Promotion, Hanseo University, Seosan, Korea.
authors.forename: Il Gyu
authors.initials: IG
authors.lastname: Ko
authors.affiliation: Department of Urology, Gachon University Gil Medical Center, Gachon University School of Medicine, Incheon, Korea.
authors.forename: Jin Woo
authors.initials: JW
authors.lastname: Jeong
authors.affiliation: Department of Urology, Gachon University Gil Medical Center, Gachon University School of Medicine, Incheon, Korea.
authors.forename: Young Hoon
authors.initials: YH
authors.lastname: Kim
authors.affiliation: Department of Exercise Physiology ∙ Prescription, Graduate School of Health Promotion, Hanseo University, Seosan, Korea.
authors.forename: Yong Seok
authors.initials: YS
authors.lastname: Jee
authors.affiliation: Department of Physiology, Kyung Hee University School of Medicine, Seoul, Korea.
authors.forename: Sung Eun
authors.initials: SE
authors.lastname: Kim
authors.affiliation: Department of Physiology, Kyung Hee University School of Medicine, Seoul, Korea.
authors.forename: Sang Hoon
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Department of Physiology, Kyung Hee University School of Medicine, Seoul, Korea.
authors.forename: Jun Jang
authors.initials: JJ
authors.lastname: Jin
authors.affiliation: Department of Physiology, Kyung Hee University School of Medicine, Seoul, Korea.
authors.forename: Chang Ju
authors.initials: CJ
authors.lastname: Kim
authors.affiliation: Department of Urology, Gachon University Gil Medical Center, Gachon University School of Medicine, Incheon, Korea.
authors.forename: Kyung Jin
authors.initials: KJ
authors.lastname: Chung
keywords: Aging; Exercise; Muscle cell; Myostatin; Skeletal muscle