摘要：Testicular fibrosis is considered to be a pathway leading to hypospermatogenesis. Two horses affected with aspermatogenesis of cryptorchidism and hydrocele, with reference to peritubular myoid cells, were examined histologically and immunohistochemically. In injured testes, the myoid cells became irregular in shape and resembled fibroblasts. Immunohistochemically, normal actin-positive myoid cells were decreased. But reactivity for α-smooth muscle actin, matrix metalloprotease-2 (MMP-2) and vimentin were clearly indicated in myoid cells. These morphological and immunohistochemical changes of myoid cells into myofibroblasts were recognized. The myoid cells seemed to develop into myofibroblasts for defense against testicular damage, and positively secreted extracellular matrix (ECM). Simultaneously, myofibroblasts seem to induce a morbid condition due to gelatinization of the basal lamina, which assists in the blood-testis barrier. The myofibroblasts, developed from myoid cell were thought to play an important role in the process of testicular fibrosis.
