Numerical densities of myonuclei and satellite cells in muscle fiber types in the aging human thyroarytenoid muscle: an immunohistochemical and stereological study using confocal laser scanning microscopy.

Abstract

This study determines the role of changes in numerical densities of myonuclei and satellite cells in age-related remodeling of the thyroarytenoid muscle (TA). Changes in numerical densities (N(V)) and ratios (N(N)) of myonuclei and satellite cells were estimated for the entire TA by use of stereological techniques. There was no age-related change or difference between fiber types for N(V myonucleus, fiber), but N(V myonucleus, fiber) increased with decreasing fiber diameter. There was a trend toward a decrease in N(V satellite cell, fiber) and a decrease in N(N satellite cell, myonucleus). N(V satellite cell, fiber) was higher for type 1 than for type 2 fibers, and type 1 satellite cells increased disproportionately with increasing total satellite cell numerical density. Decreased satellite cell proliferation may contribute to age-related fiber loss and atrophy in the TA. Therapeutic techniques based on activation of satellite cells may block age-related fiber loss and atrophy in the TA.