Electrophysiological subtypes and prognosis of Guillain–Barré syndrome in Northeastern China

Introduction: The dystrophic features in hindlimb skeletal muscles of female mdx mice are unclear. Methods: We analyzed force‐generating capacity and force decline after lengthening contraction‐induced damage (fragility). Results: Young (6‐month‐old) female mdx mice displayed reduced force‐generating capacity (?18%) and higher fragility (23% force decline) compared with female age‐matched wild‐type mice. These 2 dystrophic features were less accentuated in young female than in young male mdx mice (?32% and 42% force drop). With advancing age, force‐generating capacity decreased and fragility increased in old (20 month) female mdx mice (?21% and 57% force decline), but they were unchanged in old male mdx mice. Moreover, estradiol treatment had no effect in old female mdx mice. Conclusions: Female gender–related factors mitigate dystrophic features in young but not old mdx mice. Further studies are warranted to identify the beneficial gender‐related factor in dystrophic muscle. Muscle Nerve, 2013