title: Age-related changes in the mitotic and metabolic characteristics of muscle-derived cells.
abstract: Age-related sarcopenia could partly result from cumulative repeated episodes of incomplete repair and regeneration. We hypothesized that mitotic and metabolic events associated with satellite cell activation and proliferation could be altered with aging. Muscle-derived cells (mdc) were isolated from gastrocnemius and quadriceps muscles of young (3 wk old), adult (9 mo old), and old (24 mo old) Sprague-Dawley male rats (n = 10/group). The mdc from young growing rats started to proliferate earlier compared with adult and old animals. Cell cycle duration was significantly reduced with aging from 36.5 +/- 3.2 to 28.0 +/- 2.2 h. However, the proportion of noncycling (G0 phase) and cycling (G1 + S + G2 + M phases) cultured mdc was statistically unchanged among the three age groups. Significantly lower increase in c-met and proliferating cell nuclear antigen expression were observed in cultured mdc of old rats upon serum stimulation. Major changes in the expression of citrate synthase, lactate dehydrogenase, proteasome, caspase 3, plasminogen activators (PAs), and matrix metalloproteinase 2-9 (MMP2-9) were observed upon serum stimulation, but no age-related difference was noted. However, when measured on crushed muscle extracts, PAs and MMP2-9 enzyme activities were significantly decreased with aging. Our results show that cellular and biochemical events associated with the control of mdc activation and proliferation occur with aging. These alterations may participate in the accumulation of repeated episodes of incomplete repair and regeneration throughout the life span, thus contributing to the loss of skeletal muscle mass and function with aging.
authors.affiliation: Laboratoire de Physiologie, Groupe Physiologie et Physiopathologie de l'Exercice et du Handicap-Groupement d'Intérêt Public Exercice Sport Santé, Faculté de Médecine, 42023 Saint-Etienne, France.
authors.forename: Aude E
authors.initials: AE
authors.lastname: Barani
authors.forename: Anne-Cécile
authors.initials: AC
authors.lastname: Durieux
authors.forename: Odile
authors.initials: O
authors.lastname: Sabido
authors.forename: Damien
authors.initials: D
authors.lastname: Freyssenet
mesh_terms: D000375:Aging / Q000378:metabolism* / Q000473:pathology; D000818:Animals; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002950:Citrate (si)-Synthase / Q000378:metabolism; D003546:Cysteine Endopeptidases / Q000378:metabolism; D015536:Down-Regulation; D005109:Extracellular Matrix / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008297:Male; D020782:Matrix Metalloproteinases / Q000378:metabolism; D008938:Mitosis / Q000502:physiology*; D009097:Multienzyme Complexes / Q000378:metabolism; D018485:Muscle Fibers, Skeletal / Q000166:cytology / Q000378:metabolism; D018482:Muscle, Skeletal / Q000166:cytology* / Q000378:metabolism*; D009133:Muscular Atrophy / Q000378:metabolism* / Q000473:pathology; D010960:Plasminogen Activators / Q000378:metabolism; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex; D019859:Proto-Oncogene Proteins c-met / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D032496:Satellite Cells, Skeletal Muscle / Q000166:cytology / Q000378:metabolism
chemical_list: D009097:Multienzyme Complexes; D018809:Proliferating Cell Nuclear Antigen; D007770:L-Lactate Dehydrogenase; D002950:Citrate (si)-Synthase; D019859:Proto-Oncogene Proteins c-met; D010960:Plasminogen Activators; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases; D003546:Cysteine Endopeptidases; D020782:Matrix Metalloproteinases; D046988:Proteasome Endopeptidase Complex