Fragmentation analysis of normal and dystrophic avian muscle

A difference between normal and dystrophic avian muscle was demonstrated by comparing the patterns of fragmentation of muscle during homogenization. Fragmentation was monitored by morphological methods and by viscometry. This method of fragmentation analysis depends on the principle that the viscosity of a suspension is an exponential function of the partial volume fraction occupied by the suspended particles; the more a tissue is fragmented into smaller pieces, the greater the viscosity of the resulting homogenate. Increasing the duration of homogenization of either fresh muscle in buffer or glycerinated muscle in relaxing solution gradually increased the viscosity of the homogenate of normal muscle, whereas the viscosity of the homogenate of dystrophic muscle remained approximately constant. This difference in viscosity indicated that dystrophic muscle was sheared into larger pieces which were resistant to further fragmentation. Electron microscopic examination showed that the homogenate of dystrophic muscle contained rows of sarcomeres, whereas normal muscle was sheared into amorphous masses of myofilaments.