Coenzyme Q10 improves the cryopreservation and fertilizing capacity of dromedary camel epididymal sperm.

Cryopreservation of epididymal spermatozoa, recovered post-mortem, enables genetic preservation in dromedary camels; however, freeze-thaw procedures induce oxidative stress that hinders spermatozoal function. This study evaluated the effects of supplementing a commercial semen extender (INRA 96) with various concentrations of Coenzyme Q10 (CoQ10; 0, 0.25, 1.00, and 2.00 μM) on post-thaw quality and fertilizing capacity of dromedary camel epididymal spermatozoa. Post-thaw assessments included motility, vitality, morphology, plasma membrane functionality, and acrosome integrity. Oxidative stress markers [total antioxidant capacity (TAC) and malondialdehyde (MDA)] were measured in the extender post-thaw. Cleavage and blastocyst rates after in vitro embryo production (IVEP) were also recorded. Supplementation of the extender with 0.25 μM CoQ10 significantly improved post-thaw motility (48.33% ± 1.67 vs. control 38.33% ± 1.67), vitality (53.33% ± 2.73 vs. control 41.00% ± 2.08), membrane functionality (50.33% ± 4.10 vs. control 47.33% ± 4.26), and acrosome integrity (63.33% ± 2.73 vs. control 46.67% ± 2.40). Additionally, CoQ10 at 0.25 μM enhanced cleavage (30.39% ± 1.86) and blastocyst formation rates (20.59% ± 2.03) compared to the control groups (23.73% ± 1.20 and 15.25% ± 1.45, respectively). Biochemically, 0.25 μM CoQ10 elevated TAC (0.76 ± 0.02 mM/L) and reduced MDA (6.88 ± 0.38 nmol/mL) compared to controls (0.40 ± 0.04 mM/L and 8.99 ± 0.31 nmol/mL, respectively). In contrast, higher CoQ10 concentrations (1.00 and 2.00 μM) impaired both sperm quality and embryo development potential. In conclusion, low-dose CoQ10 supplementation (0.25 μM) showed beneficial outcomes, while concentrations exceeding 1.00 μM were deleterious. Future research should investigate the molecular mechanisms by which CoQ10 protects spermatozoa, including its effects on mitochondrial function and specific antioxidant pathway activation during the cryopreservation process.