A cytological study of the effect of reinnervation and cross-innervation on rat striated muscle

The changes of rat muscle fiber structure and fiber types after the reunification of the nerve and cross-innervation between the nerve to M. soleus (SOL) and M. extensor digitorum longus (EDL) were cytologically studied and the following results were obtained: 1. After the reunification of the nerve, the tendency toward grouping to a single fiber type was observed, although in normal muscle, the red, white and intermediate fibers were distributed in mosaic pattern. 2. After the cross innervation, the changes of fiber types occurred; namely, in SOL, normally composed of red and intermediate fibers, the three types of fibers appeared after the cross- innervation with the nerve to EDL, which originally was composed of the red, white and intermediate muscle fibers, and vice versa. These changes were observed not only in histochemical sections, but also in the ultrastructural level by electron microscope.</p

A cytological study on the effect of nerve crush injuries in striated muscle fibers

The changes in muscle fibers after the crush injuries of the nerve were studied with rat sciatic nerve, and the following results were obtained. 1. After a severe crushing, the tendency of grouping of a single muscle fiber type was observed, although this scarcely occurred after slight injuries. 2. The muscle function and structure recovered better after crush injuries of the nerve than after the nerve reunification.</p

A Cytological Study of the Effect of Reinnervation andCross-innervation on Rat Striated Muscle

The changes of rat muscle fiber structure, fiber types and the distribution after the reunification of the nerve and cross-innervation between the nerve to M. soleus (SOL) and M. extensor digitorum longus (EDL) were cytologically studied and the following results were obtained: (1) In cross-innervation experiments, changes of the fiber types occured, namely, the white fibers distinctly appeared , in the SOL normally composed of the red and intermediate fibers, as if the SOL converted to EDL which was ordinarily consisted of three types of muscle fibers. This result was ascertained by an electron-microscopic study, and the white fibers, found in cross-innervated SOL, had the motor endplates and sarcoplasmic reticulum as in the original white muscle fibers. (2) In the reunification study of the nerve to SOL and EDL, the muscle fibers, fallen in denervation-atrophy stage, were regenerated to almost normal in constructure. The distribution of the muscle fibers, however, was changed; a tendency to be grouping a single fiber type was noticed in the muscle fibers. (3) These results suggested that the distribution of muscle fibers were greatly influenced by the peripheral nerve control

A Cytological Study on the Effect of Nerve Crush Injuriesin Striated Muscle Fibers

The changes in muscle fibers after the crush injuries of the peripheral nerve were studied by using rat sciatic nerves, and the following results were obtained. (1) A parallel relationship was observed between the recovery of the muscular function and the histochemical features of the muscle fibers. (2) After severe crush injuries, a tendency to be grouping a single fiber type was observed, although that scarcely occured after slight injuries. (3) Both the muscular function and structure recovered better after crush injuries of the nerve than after the reunification

A Cytological Study of the Effect of Tenotony and Gips-fixation on Rat Striated Muscle

Atrophy of rat muscle fibers by a tenotomy of the achilles tendon and a gips-fixation of the whole hind limbs were histochemically studied, and the following results were obtained. (1) Gips-fixation and tenotomy experiments, the red and intermediate muscle fibers were markedly fallen in atrophic stages. (2) After the tenotomy, denervated red and intermediate muscle fibers were scattered partially in the M. soleus. (3) By the tenotomy, the white muscle fibers kept almost normal in comparison with the red ones.(4) The atrophy of the muscle fiberss was more remarkable in the gips-fixation than in the tenotomy. This tendency was more marked in the M. soleus than the other muscles. (5) Mitochondria were more destroyed in quality than in quantity in atrophied muscle fibers