Protective Effect of Cerium Oxide Nanoparticles on Human Sperm Function During Cryopreservation

The generation of reactive oxygen species during cryopreservation of human sperm has negative effects on the consistency of the thawed sperm. The antioxidant properties of cerium oxide nanoparticles (CeO2NPs) may be useful for reducing cryodamage in thawed sperm. This research was conducted to determine the effects of CeO2NPs on the quality and function of human sperm after thawing. Samples of semen obtained from 20 normozoospermic individuals were allocated to the following four groups: fresh, frozen control (sperm not treated with CeO2NPs), and those exposed to 0.1 μg/mL CeO2NPs (CeO2-0.1), 1 μg/mL CeO2NPs (CeO2-1), and 5 μg/mL CeO2NPs (CeO2-5). Sperm parameters of motility, viability, membrane integrity, DNA fragmentation, protamination, malondialdehyde (MDA) levels, mitochondria membrane potential, and morphology were evaluated after the freezing-thawing process. The results showed that 0.1 μg/mL CeO2NPs significantly (p < 0.05) improved the following human sperm parameters after thawing: progressive (44.6% ± 1.14% vs. 36.2% ± 1.24%) and total motility (60.9% ± 2.5% vs. 51.3% ± 2.5%), viability (67.9% ± 1.5% vs. 58.1% ± 1.5%), membrane functionality (66.1% ± 1.85% vs. 55.4% ± 1.85%), DNA integrity (30.8% vs. 24.04%), and protamination (69.85% ± 2.09% vs. 57.2% ± 2.09%) compared with the frozen control group. We observed the lowest MDA levels in the CeO2-0.1 (3.06 ± 0.25 nmol/mL), CeO2-1 (3.1 ± 0.25 nmol/mL), and CeO2-5 (3.08 ± 0.25 nmol/mL) groups compared with the frozen control group (3.72 ± 0.25). Different concentrations of CeO2NPs did not significantly change sperm normal morphology and mitochondria activity (p < 0.05).