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

OBJECTIVE: This study determines the role of changes in numerical densities of myonuclei and satellite cells in age-related remodeling of the thyroarytenoid muscle (TA). DESIGN: 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. RESULTS: There was no age-related change or difference between fiber types for N-V myonucleus,N- fiber, but N-V myonucleus,N- fiber increased with decreasing fiber diameter. There was a trend toward a decrease in N-V satellite cell,N- fiber and a decrease in N-N satellite cell, myonucleus N-V satellite cell,N- 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. CONCLUSION: Decreased satellite cell proliferation may contribute to age-related fiber loss and atrophy in the TA. SIGNIFICANCE: Therapeutic techniques based on activation of satellite cells may block age-related fiber loss and atrophy in the TA.