Activity of antioxidant enzymes and their mRNA expression in different reproductive tract tissues of the male roe deer (Capreolus capreolus) during the pre-rut and rut seasons

Roe deer (Capreolus capreolus) are seasonal breeders with a short rut season during which there is a significant change in the secretory activity of the testis and epididymis. This study compared the activity of antioxidant enzymes and their mRNA expression levels in the reproductive tract tissues of the adult male roe deer during the pre-rut (n = 6 animals) and rut (n = 6 animals) seasons. Comparisons were made between tissues within seasons and within tissues between seasons. The activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) was evaluated in testicular and epididymal tissues; and real-time reverse transcriptase-polymerase chain reaction (RT-PCR) was used to analyze mRNA expression levels of the antioxidant enzymes: copper/zinc SOD (SOD1), extracellular SOD (Ec-SOD), CAT, phospholipid hydroperoxide glutathione peroxidase (PHGPx) and GPx5. SOD activity was significantly higher (P < 0.05) in all the tissues in the rut season than in the pre-rut season. CAT activity was not significantly different between tissues in the pre-rut season, but was significantly (P < 0.05) higher in the caput and corpus epididymal tissues than the other tissues in the rut season and the same tissues in the pre-rut season. Testicular tissue GPx activity was significantly higher (P < 0.05) compared with the other tissues in both seasons. Significantly higher (P < 0.05) SOD1 mRNA levels were expressed in the three epididymal tissues than in the testicular tissue in both seasons. The caput epididymal tissue expressed higher (P < 0.05) levels of Ec-SOD mRNA compared with the other tissues during the pre-rut season, but the differences between the tissues in the rut season were not significant. The corpus and cauda epididymal tissue expression of Ec-SOD mRNA was significantly higher (P < 0.05) in the rut season compared with the pre-rut season. CAT mRNA expression level in the caput epididymis during the pre-rut season was significantly higher (P < 0.05) than in the other tissues and than in the rut season. Testicular tissue exhibited significantly higher (P < 0.05) expression level of PHGPx mRNA than the other tissues in both seasons. PHGPx mRNA expression in testicular tissue in the rut season was approximately 3× the level expressed in the pre-rut season (P < 0.05). The caput epididymal tissue expressed very high levels of GPx5 in both seasons, whereas the testicular tissue showed very low levels of GPx5 (both differences at P < 0.05). This study showed that the activity of antioxidant enzymes and their mRNA expression in the testis and epididymal tissues are dependent on the reproductive season in the male roe deer and suggests that the antioxidant enzyme system is more efficient during the rut season.