title: Effects of low-intensity swimming on radiation-induced leg contracture in mice.
abstract: OBJECTIVE
  To evaluate the effects of low-intensity swimming on radiation-induced leg contracture.
  
  
  METHODS
  Forty mice were randomly and equally divided into four groups: 1) irradiation; 2) swimming before irradiation; 3) swimming after irradiation; 4) swimming after contracture, and their left hind legs were exposed to gamma irradiation of 60 Gy. The mice were allowed to swim freely for 10 minutes, three times per day. For group 2, the mice were allowed to swim for only 1 week before irradiation. For group 3, the mice were allowed to swim immediately after irradiation until day 130, post-irradiation. For group 4, the mice were allowed to swim after leg contracture happened (on day 30 post-irradiation) until day 130, post-irradiation. The leg lengths and knee joint angles were measured. Leg contracture was defined as the decrease in the hind leg lengths and the knee joint angles of each animal. The ultrastructural changes of gastrocnemius muscles were observed using transmission electron microscopy.
  
  
  RESULTS
  The radiation could result in leg contracture and mitochondrial injury of the muscles. However, the group of swimming immediately after irradiation had less leg contracture and no vacuolar degeneration in the mitochondria, compared with the other groups.
  
  
  CONCLUSIONS
  Low-intensity swimming that began immediately after the mice were irradiated could effectively prevent the irradiated legs from contracture. Patients with irradiated mastication muscles were recommended to begin mouth-opening exercises immediately after radiotherapy.
authors: Department of Oral and Maxillofacial Radiology, Peking University School and Hospital of Stomatology, Beijing, PR China.
authors: Xing Min
authors: XM
authors: Qu
authors: Gang
authors: G
authors: Li
authors: Zhi Min
authors: ZM
authors: Li
authors: Kang Tao
authors: KT
authors: Ma
authors: Ping
authors: P
authors: Chen
authors: Chun Yan
authors: CY
authors: Zhou
authors: Xu Chen
authors: XC
authors: Ma
mesh_terms: D000818:Animals; D003286:Contracture / Q000209:etiology / Q000517:prevention & control / Q000628:therapy*; D005081:Exercise Therapy; D005260:Female; D005720:Gamma Rays; D006614:Hindlimb / Q000528:radiation effects*; D007719:Knee Joint / Q000528:radiation effects; D051379:Mice; D008809:Mice, Inbred C3H; D008928:Mitochondria / Q000528:radiation effects; D009210:Myofibrils / Q000528:radiation effects / Q000648:ultrastructure; D011833:Radiation Injuries, Experimental / Q000628:therapy*; D011897:Random Allocation; D013550:Swimming