Spatial patterns of fiber types in atrophied skeletal muscle

This study examined the spatial distributions of different fiber types in the soleus muscle of control rats and in rats subjected to hindlimb unloading for 28 days. The frequencies with which muscle fibers of one type were adjacent to each other and to fibers of other types were tabulated and compared to expectations generated from Monte Carlo simulations. In the normal rat, there is a tendency for Type I fibers to avoid adjacency with each other, a tendency that persisted in the hindlimb-suspended group, despite the substantial shrinkage in size of Type I fibers. We conclude that this treatment, unlike neurogenic pathologies, does not cause any remodeling of the adjacency relations of fibers.