Quantification of ultrastructural damage in human skeletal muscle

Abstract

Qualitative microscopic analysis of muscle architecture provides information about cellular markers of muscle fiber disruption in myopathic, aging, and experimentally damaged muscle. However, this approach does not provide sensitive information regarding the extent of muscle damage and has serious limitations when research protocols address tissue remodeling. The purpose of this study was to quantitatively assess the extent of muscle damage in young and older adults before and after exercise-induced damage. The older adults in this study had lower aerobic capacities and muscle mass than their younger counterparts, suggesting greater vulnerability toward muscle damage produced by physiologic stress.Five young males, ages 20 to 29 years and five older males, age 60 to 75 years had percutaneous needle biopsies taken from the vastis lateralis muscle before and after (N=9) exercise consisting of reverse cycling or downhill treadmill running at a prescribed physiologic effort. Muscle samples were prefixed in 3.0% gluteraldehyde in cacodylate buffer and post-fixed in VL OSO4. This was followed by routine procedures for TEM.