Testicular alterations in the nonobese diabetic mouse.

The nonobese diabetic (NOD) mouse was used as a model for evaluating alterations in testicutar structure. The NOD mouse exhibits diabetic manifestations on an apparently autoimmune basis and thus resembles human type 1 insulin-dependent diabetes mellitus. Testicular samples were obtained from animals with and without diabetic manifestations at various ages. The principal changes noted on histological examination were in the seminiferous tubules, including germ cell degeneration, disruption of spermatogenesis, tubular fibrosis, and intratubular calcification. These effects were diffuse and extensive in animals with severe hyperglycemia. In those with normal and borderline elevated glucose levels, focal tubular damage was found to occur in a patchy distribution. The changes included disorganization of maturation, malorientation of spermatids, and hypospermatogenesis. Electron microscopic studies also indicated effects on Sertoli cells and the peritubular tissue. There was no evidence of mononuclear cell infiltration or vascular abnormalities in any of the testicular specimens. The findings indicate that the NOD mouse may be a useful model for understanding the development of pathological changes in the testis in insulin-dependent diabetes.