Journals of Gerontology Series A: Biological Sciences and Medical Sciences, Vol 53, Issue 4 B252-B258, Copyright © 1998 by The Gerontological Society of America
Effect of age and neurovascular grafting on the mechanical function of medial gastrocnemius muscles of fischer 344 rats
LM Larkin, WM Kuzon, MA Supiano, A Galecki and JB Halter
Divisions of Geriatric Medicine, Department of Internal Medicine, and Institute of Gerontology, University of Michigan, Ann Arbor.
Both aging and grafting of whole skeletal muscle are associated with
decreased specific force and resistance to fatigue. This study tested the
hypothesis that the recovery of mechanical function in nerve-repair
skeletal muscle grafts in senescent rats would be impaired compared with
recovery in similar grafts in younger animals. Following a 120-day
recovery period, the contractile properties of grafted medial gastrocnemius
(MGN) muscles from young-mature (6 months), middle-aged (12 months), and
sensescent (24 months) Fischer 344 rats were measured and compared to
age-matched controls. Although there was full recovery of muscle mass,
grafting and aging alone both were associated with diminished maximum
twitch and tetanic tension, maximum power, and maximum sustained power. In
addition, the deleterious effect of grafting on maximum tetanic tension,
specific force, and sustained power of MGN muscle was significantly greater
in old animals. These findings suggest that aging limits full recovery of
the quality of muscle contractions from the nerve-repair grafting
procedure, possibly due to an age-related impairment of reinnervation.
