title: Time-dependent changes in caspase-3 activity and heat shock protein 25 after spinal cord transection in adult rats.
abstract: Chronic reductions in muscle activation and loading are associated with decreased heat shock protein 25 (Hsp25) expression and phosphorylation (pHsp25) which, in turn, may contribute to elevated caspase-3-mediated muscle protein breakdown. Thus, the purpose of the present study was to determine whether there are any changes in Hsp25, pHsp25 and caspase-3 activity among rat muscles having different fibre type compositions and functions [soleus, adductor longus (AL), plantaris and tibialis anterior (TA)] at 0 (control), 1, 8 or 28 days after a complete spinal cord transection (ST). The Hsp25 levels were unaffected on days 1 and 8 in all muscles, except for a significant reduction on day 8 in plantaris. The Hsp25 levels were lower than control values in all muscles except TA on day 28. The pHsp25 levels were lower than control values after 8 and 28 days in plantaris and AL and after 28 days in soleus, but higher than control in TA after 8 and 28 days. Caspase-3 activity was higher in ST than control rats on day 8 in all muscles except TA. Caspase-3 activity was negatively correlated with muscle mass for all muscles. In plantaris, Hsp25 and pHsp25 were negatively correlated with caspase-3 activity and Hsp25 was correlated with muscle mass. These relationships were not observed in other muscles. Thus, the effects of ST on Hsp25 and caspase-3 are muscle specific and time dependent, factors that should be considered in developing any intervention to maintain muscle mass after a spinal cord injury.
authors.affiliation: Department of Kinesiology, University of Illinois Urbana-Champaign, 906 South Goodwin Avenue, Urbana, IL 61801, USA. khuey@uiuc.edu
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Huey
authors.forename: Roland R
authors.initials: RR
authors.lastname: Roy
authors.forename: Hui
authors.initials: H
authors.lastname: Zhong
authors.forename: Carolyn
authors.initials: C
authors.lastname: Lullo
mesh_terms: D000367:Age Factors; D000818:Animals; D001835:Body Weight; D053148:Caspase 3 / Q000378:metabolism*; D004195:Disease Models, Animal; D005260:Female; D055551:HSP27 Heat-Shock Proteins; D006360:Heat-Shock Proteins / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D009133:Muscular Atrophy / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D009363:Neoplasm Proteins / Q000378:metabolism*; D009929:Organ Size; D010766:Phosphorylation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013119:Spinal Cord Injuries / Q000150:complications / Q000378:metabolism* / Q000473:pathology; D013997:Time Factors
chemical_list: D055551:HSP27 Heat-Shock Proteins; D006360:Heat-Shock Proteins; C486114:Hspb1 protein, rat; D009363:Neoplasm Proteins; C505410:Casp3 protein, rat; D053148:Caspase 3