Inhibition of Mitochondrial Complex I Leads to Decreased Motility and Membrane Integrity Related to Increased @entity273 and Reduced XXXX Production, while the Inhibition of Glycolysis Has Less Impact on Sperm Motility.

@entity1 @entity13389 @entity3788 @entity26 @entity8581 @entity273 @entity11382 @entity224 @entity855
UNASSIGNED: Mitochondria have been proposed as the major source of reactive @entity26 species in somatic cells and @entity1 spermatozoa. However, no data regarding the role of mitochondrial ROS production in stallion spermatozoa are available. To shed light on the role of the mitochondrial electron transport chain in the origin of oxidative stress in stallion spermatozoa, specific inhibitors of complex I ( @entity3788 ) and III ( @entity11382 -A) were used. Ejaculates from seven Andalusian stallions were collected and incubated in BWW media at 37  C in the presence of @entity3788 , @entity8581 or control vehicle. Incubation in the presence of these inhibitors reduced sperm motility and velocity ( @entity13389 analysis) (p<0.01), but the effect was more evident in the presence of @entity3788 (a complex I inhibitor). These inhibitors also decreased @entity855 content. The inhibition of complexes I and III decreased the production of reactive @entity26 species (p<0.01) as assessed by flow cytometry after staining with CellRox deep red. This observation suggests that the CellRox probe mainly identifies @entity224 and that @entity224 production may reflect intense mitochondrial activity rather than oxidative stress. The inhibition of complex I resulted in increased @entity273 production (p<0.01). The inhibition of glycolysis resulted in reduced sperm velocities (p<0.01) without an effect on the percentage of total motile sperm. Weak and moderate (but statistically significant) positive correlations were observed between sperm motility, velocity and membrane integrity and the production of reactive @entity26 species. These results indicate that stallion sperm rely heavily on oxidative phosphorylation (OXPHOS) for the production of @entity855 for motility but also require glycolysis to maintain high velocities. These data also indicate that increased @entity273 originating in the mitochondria is a mechanism involved in stallion sperm senescence.
