[Histochemical and ultrastructural observations of limb muscle in spontaneous diabetic mice]

Spontaneous non-obese diabetic (NOD) mice were used to study the morphological change of muscle fibers in diabetes mellitus. The gastrocnemius and soleus muscles were removed from the NOD mice suffering from diabetes mellitus for 1, 3, 6 or 9 weeks. Muscle fibers were observed electronmicroscopically and histochemically, by staining with Sudan black B. Single fiber atrophy was noted in white fibers at an early stage of the illness. At the age of 6 and 9 weeks, white fibers showed extensive damage, characterized by the atrophy and wide separation of myofibrils, irregularity and thinness of myofilaments and massive glycogen deposition. The damage in the myofibril itself, however, was less pronounced in red and intermediate fibers, and those fibers had more abnormal mitochondria and a decreased affinity for sudan pigment. Morphological changes were varied in the three types of fibers. It is concluded that diabetes mellitus had different effects on each three types of muscle fibers neurogenically and metabolically.