Heat Shock Proteins Are Differentially Expressed in the Domestic Cat (Felis catus) Testis, Epididymis, and Vas Deferens.

Abstract

Heat shock proteins (HSPs) play key roles in controlling the morphological transformation of germ cells during spermatogenesis and posttesticular maturation of sperm. This study aims to reveal the presence and localization patterns of large adenosine triphosphate (ATP)-dependent HSPs family members in adult domestic cat testis and excurrent ducts utilizing Western blot, immunohistochemistry, and immunofluorescence techniques. The results indicated that the relative amounts of heat shock protein D1 (HSPD1)/HSP60, heat shock protein C (HSPC)/HSP90, and heat shock protein H (HSPH)/HSP105/110 were highest in the testis, while heat shock protein A (HSPA)/HSP70 was highest in the corpus epididymis. HSPs exhibited spermatogenic stage-dependent localization patterns in germ cells. Sertoli and Leydig cells were positive for other HSPs except for HSPC/HSP90. The tubules rectus and rete testis epithelia showed only HSPD1/HSP60 and HSPA/HSP70 immunoreactivity, while the ciliated cells of efferent ductules were positive for all HSPs. In the epididymis and vas deferens, HSPs localizations were cell and region specific. HSPD1/HSP60 was localized in the midpiece of the immature spermatozoa tail, while HSPA/HSP70 and HSP90 were found only in the proximal cytoplasmic droplet (CD). HSPH/HSP105 was observed in CD and the principal piece but not the midpiece. Overall, the different expression of HSPs throughout the domestic cat testis and excurrent ducts indicates their critical roles in maintaining reproductive functions under physiological conditions.