Wang, Hai, Liu, Kexiong, Zeng, Weibin, Bai, Jiahua, Xiao, Linli, Qin, Yusheng, Liu, Yan, and Xu, Xiaoling
Simple Summary: Cryopreserved semen, widely utilized in the artificial insemination of domestic animals, encounters challenges due to oxidative damage. This study investigated the effects of the antioxidant PQQ on the semen quality of Holstein bulls during cryopreservation and elucidated the associated mechanisms. Our findings revealed that PQQ significantly enhanced sperm motility, membrane integrity, acrosome integrity, and ATP levels, while simultaneously reducing MDA and ROS levels. Additionally, increased PGAM2, CAPZB, CAT, SOD1, and GPX1 protein expressions were also observed in the PQQ-treated group. Based on these results, PQQ not only improved semen quality but also mitigated oxidative stress, thereby enhancing the efficacy of sperm cryopreservation in bulls. Cryopreserved semen is extensively utilized in the artificial insemination (AI) of domestic animals; however, suboptimal conception rates due to oxidative damage following AI continue to pose a challenge. The present study investigated the effects of Pyrroroquinoline Quinone (PQQ), a novel antioxidant, on the semen quality of Holstein bulls during cryopreservation, as well as its potential molecular mechanisms. Semen samples were diluted with varying concentrations of PQQ (0, 50 μmol/L, 100 μmol/L, 150 μmol/L) prior to cryopreservation. Following the freeze–thaw process, a comprehensive evaluation was conducted to assess sperm motility, plasma membrane integrity, acrosome integrity, and the levels of reactive oxygen species (ROS), malondialdehyde (MDA), and adenosine triphosphate (ATP). Western blot analysis was employed to examine the levels of proteins including PGAM2, CAPZB, CAT, SOD1, and GPX1. Notably, the inclusion of 100 μmol/L PQQ significantly enhanced sperm motility, membrane integrity, and acrosome integrity post freeze–thawing (p < 0.05). Furthermore, the group treated with 100 μmol/L PQQ exhibited reduced levels of MDA and ROS (p < 0.05), while ATP levels were significantly elevated (p < 0.05). Interestingly, treatment with 100 μmol/L PQQ resulted in decreased consumption of PGAM2, CAPZB, CAT, SOD1, and GPX1 proteins in sperm after freeze–thawing, compared to the control group (p < 0.05). These findings indicate that PQQ treatment enhances the quality of bull semen, mitigates oxidative stress damage, and ultimately improves the efficacy of sperm cryopreservation. [ABSTRACT FROM AUTHOR]