ML, Podhorska-Okolow M, Carraro U: Stage and quantify regenerative myogenesis in FES-induced functional recovery of human long-term permanent denervated muscle. Basic Appl Myol 2002; 12 (6): xxx-xxx

Following denervation, skeletal muscle undergoes rapid loss in both mass and contractile force, with an accompanying series of changes in structure, biochemistry and physiology. Morphologic features of the long-term denervated muscle suggest that the original fibers are lost and those seen are the results of repeated cycles of cell death and regeneration. Markers of myogenic events in adult muscles are activated satellite cells, presence of embryonic my-osin and myogenic transcription factors. Electrical stimulation of permanent denervated mus-cle increases the mean size of the myofibers, maintains the sarcomeres and possibly prevents apoptosis/necrosis and secondary degeneration. We here describe histological, immunohistochemical and molecular methods, which identify markers of damage, regeneration, and repair on a muscle sample of just a few milligrams. A suitable source is a small biopsy, whose cryostat sections allow fiber typing and histopathol-ogy by immunochemical analyses. A few additional serial cryostat sections are used for mo-lecular analyses. By light morphometry percent fat and/or interstitial tissue area, and fiber size distribution are determined. Myosin ATPases and immunohistochemistry are used to quantif