title: Life-Long Wheel Running Attenuates Age-Related Fiber Loss in the Plantaris Muscle of Mice: a Pilot Study.
abstract: The purpose of this study was to investigate whether long-term wheel running would attenuate age-related loss of muscle fiber. Male ICR mice were divided into young (Y, n=12, aged 3 months), old-sedentary (OS, n=5, aged 24 months), and old-exercise (OE, n=6, aged 24 months) groups. The OE group started spontaneous wheel running at 3 months and continued until 24 months of age. Soleus and plantaris muscles were fixed in 4% paraformaldehyde buffer. The fixed muscle was digested in a 50% NaOH solution to isolate single fiber and then fiber number was quantified. The masses of the soleus and plantaris muscles were significantly lower at 24 months than at 3 months of age, and this age-related difference was attenuated by wheel running (P<0.05). Soleus muscle fiber number did not differ among the groups. In the plantaris muscle, the fiber number in the OS group (1 288±92 fibers) was significantly lower than in the Y group (1 874±93 fibers), and this decrease was attenuated in the OE group (1 591±80 fibers) (P<0.05). These results suggest that age-related fiber loss occurs only in the fast-twitch fiber-rich muscle of mice, and that life-long wheel running exercise can prevent this fiber loss.
authors.affiliation: Toyota Motor Coporation, Health Support Center WELPO, Toyota, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Suwa
authors.affiliation: Tohoku Institute of Technology, Faculty of Life Design, Sendai, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Ishioka
authors.affiliation: Tohoku Institute of Technology, Faculty of Life Design, Sendai, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Kato
authors.affiliation: Tohoku Institute of Technology, Faculty of Life Design, Sendai, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Komaita
authors.affiliation: Toyota Motor Coporation, Health Support Center WELPO, Toyota, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Imoto
authors.affiliation: Toyota Motor Coporation, Health Support Center WELPO, Toyota, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Kida
authors.affiliation: Toyota Motor Coporation, Health Support Center WELPO, Toyota, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Yokochi
mesh_terms: D000375:Aging / Q000473:pathology / Q000502:physiology*; D000818:Animals; D051379:Mice; D008813:Mice, Inbred ICR; D009043:Motor Activity; D018656:Muscle Fibers, Fast-Twitch / Q000473:pathology / Q000502:physiology*; D018482:Muscle, Skeletal / Q000473:pathology / Q000502:physiology*