title: Characteristics of muscle fibers in rats with limb movements during sleep after spinal cord injury.
abstract: OBJECTIVE
  Previous studies have demonstrated that spinal cord injury (SCI) results in changes in sleep patterns through increased arousals and limb movements during sleep. Dramatic changes in muscle myosin heavy-chain isoforms have also been reported. The aim of this study was to investigate the characteristics of muscle fibers after SCI in rats with limb movements during sleep.
  
  
  METHODS
  Forty male Wistar rats were divided into four groups: SHAM, SCI 3, 7 and 15 days. Animals were subjected to electrode insertion surgery, 24-hour baseline sleep recording, SCI, and subsequent sleep recording for 3, 7, or 15 consecutive days. In addition, the gastrocnemius muscle and spinal cord were collected for histopathological/histochemical analyses.
  
  
  RESULTS
  Our results indicate a rapid and progressive decrease in the cross-sectional area of type I fibers in the gastrocnemius muscle (35.76-24.74 μm(2)) after SCI. Additionally, we found SCI-induced changes in sleep patterns. Following SCI, we also observed limb movements in sleeping rats, as well as significant negative moderate correlations between type I fibers and limb movement.
  
  
  CONCLUSIONS
  Our study strengthened the hypothesis by correlation between changes in types of muscle fiber (decline in type I fibers) and an increase in limb movements during sleep after SCI.
authors.affiliation: Departamento de Psicobiologia, Universidade Federal de São Paulo, São Paulo, Brazil.
authors.forename: Andrea M
authors.initials: AM
authors.lastname: Esteves
authors.forename: Camila F R
authors.initials: CF
authors.lastname: Squarcini
authors.forename: Carmen L P
authors.initials: CL
authors.lastname: Lancellotti
authors.forename: Sergio
authors.initials: S
authors.lastname: Tufik
authors.forename: Marco T
authors.initials: MT
authors.lastname: de Mello
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D008297:Male; D009069:Movement Disorders / Q000209:etiology / Q000473:pathology*; D018485:Muscle Fibers, Skeletal / Q000473:pathology*; D051381:Rats; D017208:Rats, Wistar; D012893:Sleep Wake Disorders / Q000209:etiology / Q000473:pathology*; D013119:Spinal Cord Injuries / Q000150:complications / Q000473:pathology*