Muscle Fiber and Satellite Cell Apoptosis in the Aging Human Thyroarytenoid Muscle: A Stereological Study with Confocal Laser Scanning Microscopy

OBJECTIVE: This study determines the role of changes in numerical densities of apoptotic myonuclei and satellite cells in age-related remodeling of the thyroarytenoid muscle (TA). DESIGN: Changes in numerical densities of apoptotic myonuclei and satellite cells were estimated for the entire TA by using stereological techniques. RESULTS: There was an increase in N(V apoptotic myonucleus, fiber type) (P < 0.05) and in the percentage of apoptotic myonuclei (P < 0.05) in type 1 but not in type 2 muscle fibers. There was also an increase in N(V apoptotic satellite cell, fiber type) (P < 0.05) and in the percentage of apoptotic satellite cells (P < 0.05) in type 1 fibers but not in type 2 fibers. CONCLUSION: Apoptosis may contribute to age-related fiber loss and atrophy in the TA. SIGNIFICANCE: Therapeutic techniques based on decreasing the frequency of apoptosis may block age-related fiber loss and atrophy in the TA.