Glutathione Peroxidase Type-5 Expressed In The Epididymis Of Sheep

Glutathione peroxidase type-5 (GPX5) specifically expresed in the epididymis, and it is essential for maturation of sperm.The objective of this thesis was to investigate the expression pattern of GPX5 in epididymis of sheep with different ages. The results are as follows:(1)The relative quantity of GPX5 expression in epididymis, testis and deferent duct were detected by real-time fluorescent quantitative PCR (RT-qPCR).The results showed that GPX5 gene rarely expressed in the epididymis, tesis and deferent duct of lamb(2-3 months old); but in the caput epididymis of young sheep (6-12 months old), the expression of GPX5 gene was significantly higher than that of corpus or cauda(p <0.01), and nearly no expression were found in testis and deferent duct; in adult sheep(2-3years old), GPX5 expression in the caput was significantly higher (p< 0.05) than that of corpus or cauda, but it was significantly lower compared to caput epididymis of young sheep. There was no significant difference in the testis and deferent duct.(2)GPX5 protein in the epididymis and tesis of sheep with different ages were detected by western blot. The results showed GPX5 protein was not expressed in the epididymis and testis of lamb; but expressed highly in caput epididymis of young sheep, there were lower GPX5 protein in corpus and cauda of young sheep, and no expression of GPX5 protein in testis of young sheep; there was slight expression in epididymis caput of audit sheep, and almost no GPX5 protein were deteced in corpus, cauda of epididymis and testis of audit sheep.(3)The localization of GPX5 protein in epididymis was investigated by immunohistochemistry. The GPX5 protein was mainly localized in the epithelium and stereocilia of caput, while in corpus and cauda the GPX5 protein mainly localized in stereocilia. The GPX5 protein were detected in sperm in caput, corpus, cauda as well as epididymal lumen, and the GPX5 protein secreted from epididymis epithelium into epididymal lumen, combined gradually with spermatozoa during epididymal transit.In conclution, the expression patterns of GPX5 in sheep epididymis with different ages were different. After puberty GPX5 mostly expressed in the caput epididymis epithelium of young sheep or adult sheep. GPX5 protein secreted into epididymal lumen and combined with spermatozoa, which protect them from reactive oxygen species (ROS) attact during trasported in the epididymis and provide the protection for their normal physiological function.