Curcumin in a tris-based semen extender improves cryosurvival of Hariana bull spermatozoa

In this study, the cryoprotective potential of natural antioxidant curcumin in Hariana bull semen was evaluated as an additive in a tris-based extender with the assessment of motility and motion parameters of spermatozoa, membrane intactness, progesterone-receptor binding, protein carbonyl content, cervical mucus penetration, cryocapacitation-associated and apoptotic-like changes. The collected ejaculates were divided into five groups in the tris-based extender (control without curcumin-I, 10 µM-II, 25 µM-III, 50 µM-IV and 75µM-V) and were cryopreserved. Groups II and III containing 10 and 25 µM curcumin substantially (p < .05) improved the post-thaw sperm parameters like viability, motility, and velocity parameters; intact acrosome and membrane; lowered protein carbonyl content; DNA fragmentation and cryocapacitation-associated changes in comparison to control. It was interesting to note that early apoptotic-like changes in sperm cells were significantly (p < .05) decreased in Group II along with an increase in a higher population of sperm cells having high mitochondrial transmembrane potential. Higher progesterone-receptor binding, Vanguard distance and in vitro capacitation response were observed only in Group II (10µM) compared to other groups. In conclusion, curcumin in a semen extender manifests cryoprotective effects and may be incorporated at 10 µM concentration in a Hariana bull semen extender for better post-thaw sperm quality.