Distribution Characteristics and Localization of GPx5 in Adult Yak Cryptorchidic Epididymis

PurposeTo study the distribution characteristics of glutathione peroxidase-5 (GPx5) in epididymis between the cryptorchidism and normal adult yak, and to discuss the regulation of GPx5 on sperm maturation and reproductive function of yak.

MethodsEight pairs of cryptorchidism and normal epididymis of 4-year-old adult yaks were collected for analyses the expression and distribution of Gpx5 by using real-time fluorescence quantitative PCR, Western-blot, immunohistochemistry SP staining, immunohistofluorescence staining and IPP image statistics.

Results1) The ductus epididymis of normal group was pseudostratified columnar ciliated epithelium and the tube wall was rich in connective tissue, but the ductus epididymis of cryptorchidism group tended to fibrosis with the collagen fibers in the wall and almost without normal sperm in the tube. 2) The expression of Gpx5 in the caput and corpus of normal epididymis of yak was significantly higher than that in cryptorchidism group (P<0.05). 3) GPx5 was expressed in epididymal basal cells, halo cells, peritubular myoid cells, static cilia and vascular endothelial cells in two groups. GPx5 was strongly expressed in epididymal epithelial main cells in normal group, but not in cryptorchidism group. GPx5 was positive in the apical cells of the caput and corpus, and strongly positive in the cauda of normal epididymis and the caput, corpus and cauda in cryptorchidism epididymis.

ConclusionThe cryptorchidic epididymis of yaks tend to fibrosis in high altitude and low oxygen environment. GPx5 is significantly decreased in the caput and corpus of cryptorchidism epididymis, and the expression of GPx5 is mainly decreased in the main cells and basal cells, suggesting that GPx5 is closely related to oxidative stress injury and antioxidant regulation of sperm.