Differences of the anti-oxidative capability, GPX3, and Cu/ZnSOD expression in Hu sheep testis with different size at six-month-old.

This study aimed to investigate the differences in the anti-oxidant capabilities and related gene expressions of six-month-old Hu sheep with different testis sizes. A total of 201 Hu ram lambs were fed up to 6 months in the same environment. Based on their testis weight and sperm count, 18 individuals were selected and divided into large ( n  = 9) and small ( n  = 9) groups, with an average testis weight of 158.67 g ± 5.21 g and 44.58 g ± 4.14 g, respectively. The total antioxidant capacity (T-AOC), total superoxide dismutase (T-SOD), and malondialdehyde (MDA) concentration in testis tissue were tested. The localization of antioxidant-related genes, GPX3 and Cu/ZnSOD in testis were detected by immunohistochemistry. The GPX3, Cu/ZnSOD expression, and relative mitochondrial DNA (mtDNA) copy number were detected by quantitative real-time PCR. Compared with the small group, the T-AOC (2.69 ± 0.47 vs. 1.16 ± 0.22 U/mgprot) and T-SOD (22.35 ± 2.59 vs. 9.92 ± 1.62 U/mgprot) in the large group were significantly higher, whereas the MDA (0.72 ± 0.13 vs. 1.34 ± 0.17 nM/mgprot) and relative mtDNA copy number in the large group was significantly lower ( p  < .05). Immunohistochemistry results indicated that the GPX3 and Cu/ZnSOD were expressed in Leydig cells and seminiferous tubule. The expressions of GPX3 and Cu/ZnSOD mRNA in the large group were significantly higher than those in the small group ( p  < .05). In conclusion, Cu/ZnSOD and GPX3 widely expressed in the Leydig cells and seminiferous tubule, high expression of Cu/ZnSOD and GPX3 in a large group has a higher potential in addressing oxidative stress and contribute to spermatogenesis.