Effects of mitoquinone and caffeic acid on spermatological parameters and OGG1/ROMO1 gene expression of post-thawed ram semen

The aim of this study was to determine the freezability of ram semen with extenders containing mitoquinone or caffeic acid. Collected ram semen samples were pooled and divided into seven equal aliquots. Each aliquot was diluted with Tris-based extender according to control and antioxidant groups (Control, Mitoquinone (MitoQ) 100 nM, 150 nM, 200 nM; Caffeic Acid (CA) 50 µM, 100 µM, 150 µM). The post-thaw spermatological, antioxidant parameters and OGG1/ROMO1 gene expression and methylation were evaluated. It was determined that the CASA post-thaw motility of MitoQ200, CA100 and CA150 antioxidant groups were statistically higher than the control group (P < 0.05). The post-thaw plasma membrane integrity of MitoQ groups was compared with CA groups, CA100 group, which had the lowest plasma membrane integrity among the antioxidant groups. The post-thaw acrosome membrane damage of all the antioxidant groups were statistically lower than control group, except CA50 and CA100 groups (P < 0.05). For the post-thaw mitochondrial membrane potential, all groups except the CA50 group were determined to be superior to the control group (P < 0.05). No statistical difference was observed among all groups including control group in terms of post-thaw DNA fragmentation, MDA and TAC values. MitoQ significantly altered the expression of the OGG1 genes, an effect mediated through DNA methylation (P < 0.05). Furthermore, caffeic acid altered the ROMO1 gene expression (P < 0.05). Based on the spermatological parameters and gene expression and methylation levels obtained in the current study, it was determined that mitoquinone 200 nM and caffeic acid 150 µM doses had a positive effect on the freezability of ram semen.