Distribution of Heat Shock Proteins 27, 60, 70, 90 in Testis and Epididymis of the Domestic Cats ( <i>Felis catus</i> ) and Dogs ( <i>Canis lupus familiaris</i> )

This study aimed to examine the immunoexpression of HSP27, HSP60, HSP70, and HSP90 in the testis and epididymis of domestic cats (Felis catus) and dogs (Canis lupus familiaris). Testis and epididymis tissues from 6 adult cats and 6 adult dogs were used in this study. Immunohistochemical staining was done to determine the expression of HSPs. In cats and dogs, while HSP60 was detected only in Leydig cells, HSP90 was determined only in spermatogonia. HSP27 was observed only in smooth muscle cells of blood vessels. HSP70 was not detected in spermatocytes, spermatids, Leydig cells, or Sertoli cells, whereas HSP70 was determined in peritubular myoid cells. In addition, unlike cats, HSP70 was observed in spermatogonia of dog testes. HSP27 was determined in basal cells of the epididymal epithelium and smooth muscle cells of the ductal wall in all sections of the epididymis. However, no HSP60 was observed in the epididymis. While HSP70 was not detected in the epididymis of the cats, HSP70 was observed in basal cells of all sections of the epididymis of the dogs. While the epididymal epithelial cells showed HSP90 immunoreactivity in all parts of the epididymis, the smooth muscle cells of the ductal wall exhibited HSP90 immunoreactivity only in the cauda epididymidis. The findings of this study indicate that HSP27, HSP60, HSP70, and HSP90 exhibit different immunoexpression patterns in the testis and epididymis of cats and dogs and that these proteins play important roles in maintaining the reproductive functions of cats and dogs.