Specific Force Deficit in Skeletal Muscles of Old Rats Is Partially Explained by the Existence of Denervated Muscle Fibers
作者:M. G. Urbanchek、E. B. Picken、L. K. Kalliainen、W. M. Kuzon
DOI:10.1093/gerona/56.5.b191
日期:2001.5.1
We tested the hypothesis that denervated muscle fibers account for part of the specific force (sF(0)) deficit observed in muscles from old adult (OA) mammals, Whole muscle force (F-0) was quantified for extensor digitorum longus (EDL) muscles of OA and young adult (YA) rats. EDL muscle sF(0) was calculated by dividing F-0 by either total muscle fiber cross-sectional area (CSA) or by innervated fiber CSA. Innervated fiber CSA was estimated from EDL muscle cross sections labeled for neural cell adhesion molecules, whose presence is a marker for muscle fiber denervation. EDL muscles from OA rats contained significantly more denervated fibers than muscles from YA rats (5.6% vs 1.1% of total CSA), When compared with YA muscle, oil muscle demonstrated deficits of 34.1% for F-0, 28.3% for sF(0), and 24.9 % for sF(0) calculated by using innervated CSA as the denominator, Denervated muscle fibers accounted for 11.3% of the specific force difference between normal YA and OA skeletal muscle, Other mechanisms in addition to denervation account for the majority of the sF(0) deficit with aging.