Expressão de receptores de vitamina D3 (VDR) e receptores de andrógenos (AR) no testículo e região epididimária de galos (Gallus domesticus) afetados pela litíase epididimária

Abstract

The epididymal lithiasis is a reproductive dysfunction recently described in roosters, which is related to a drastic decrease in fertility in affected animals. This anomaly is characterized by the formation of stones rich in calcium in the epididymal region, which were found especially in the efferent ductules. The efferent ductules are responsible for thereabsorption of a great amount of the testicular fluid and, in birds, they are also involved in the reabsorption of calcium; thus, playing an important role in the maintenance of fertility. Considering these functions of the efferent ductules, associated with the fact that epididymal stones are formed especially in these segments, we hypothesized that thedevelopment of epididymal lithiasis would be related to local disruption of fluid and/or calcium homeostasis. The transepithelial transport of calcium is regulated by vitamin D3 and androgens as well as their receptors VDR and AR, respectively. Therefore, this studyinvestigated possible alterations in the expression of VDR and AR in roosters affected by epididymal lithiasis. The results showed that VDR and AR were widely expressed in the epididymal region of roosters; however, with distribution cell and segment specific. Whencompared to non-affected animals, roosters affected by epididymal lithiasis presented an increase in VDR and AR expression in the epididymal region, whereas no alterations in these receptors levels were detected in the testes. The increased VDR expression was mainly related to an increase in VDR-positive cells localized in the mononuclear cellinfiltrations, although a slight increase in VDR level was found in the distal efferent ductule epithelium. On the other hand, AR was overexpressed in the epithelium of the epididymal duct. The results suggest that the responsive systems for VDR and AR may be directly orindirectly involved in the development of epididymal lithiasis.