Spontaneous occurrence of vasculitis-like lesions in male reproductive tissues in mice: a histological study.

Vasculitis involving testes, epididymides, and vasa deferentia is considered to be a rare disease but has often been reported in man. In the present study, reproductive tissues of young and aged mice were examined to determine whether spontaneous vasculitis occurs in them. Testes, ductuli efferentes, epididymides, and vasa deferentia were obtained from young and aged BALB/c mice together with some nonreproductive organs for histological observation at the light microscopic level. The examination revealed that vasculitis-like lesions comparable to those in man were significantly present in the epididymides and vasa deferentia of aged but not young mice. However, no significant lesions were found in the testes and ductuli efferentes. Furthermore, other organs, such as salivary glands, thyroid glands, livers, pancreases, and kidneys, were also negative for the lesions. These results indicate that the epididymis and vas deferens are spontaneously apt to be affected by vasculitis-like lesions with advancing age, but that the lesions are not due to a systemic vasculitis disease.