Addition of MitoTEMPO to the maturation medium improves in vitro maturation competence of bovine oocytes.

The effects of MitoTEMPO, a mitochondria-targeted antioxidant, and its non-targeted parent, TEMPO, on bovine oocyte maturation competence have not been determined so far. Hence, our study was aimed to investigate the effects of supplementing maturation medium with different concentrations of MitoTEMPO (0.00, 0.10, 1.00 and 10.00 µM) or TEMPO (0.00, 5.00, 10.00 and 15.00 mM) on in vitro maturation (IVM) and fertilization (IVF) of bovine oocytes. The oocytes after IVM and IVF were evaluated for the signs of nuclear maturation and normal fertilization. The average number of spermatozoa penetrated per oocyte and the level of intracellular reactive oxygen species (ROS) were also evaluated. The results showed that percentages of bovine oocytes reached the metaphase II stage of meiosis were significantly higher in the 1.00 µM MitoTEMPO group compared to the control group (without antioxidant supplementation). The normal fertilization rate also tended to be greater in this group than the control group. In comparison with the control group, the medium supplementation with 1.00 µM MitoTEMPO led to a significant decrease in the intracellular ROS level. The average number of spermatozoa penetrated per oocyte was not significantly different among the antioxidant-treated and the non-treated groups. The TEMPO addition to the maturation medium affected neither the rate of maturation/fertilization nor the level of intracellular ROS in bovine oocytes. Based on these results, we concluded that MitoTEMPO at a concentration of 1.00 µM had beneficial effects on the quality and fertilization potential of bovine oocytes.

Attenuation of cryopreservation-induced oxidative stress by antioxidant: Impact of Coenzyme Q10 on the quality of post-thawed buck spermatozoa.

The aim of this study was to determine the quality of post-thawed buck spermatozoa by attenuation of cryopreservation-induced oxidative stress using CoQ10, a lipophilic antioxidant. Ejaculates at every sampling period were collected from four Mahabadi bucks, pooled and diluted in soybean lecithin-based extenders containing 0 (negative control, NC), 0.5 (CQ0.05), 1 (CQ1), and 1.5 (CQ1.5) µM CoQ10 and 0.9% (v/v) DMSO (positive control, PC). The diluted semen was gradually cooled to 4 °C, then frozen and stored in liquid nitrogen. After thawing, total motility although was significantly higher in CQ1 (53.40 ±â€¯1.83) than control groups (43.60 ±â€¯1.83% and 42.20 ±â€¯1.83%; P < 0.05), but this parameter did not differ between CQ1 and CQ1.5. Sperm viability was significantly higher in CQ1 (54.20 ±â€¯2.03%) than that of control and CQ0.5. The CQ1 and CQ1.5 led to significantly higher the plasma membrane functionality compared to control groups. Sperm abnormality was significantly lower in CQ1 than that of NC. The results also showed that MDA level was significantly lower in CQ1 and CQ1.5 compared with control and CQ0.5. The CQ1 (59.43 ±â€¯3.93%) was significantly increased mitochondrial activity compared to control groups. Although a greater value for %DFI was found in NC (10.24 ±â€¯0.48%) and PC (9.77 ±â€¯0.48%) groups compared to others, it was lower in CQ1 group (4.26 ±â€¯0.48%). In conclusion, based on our research results, 1 µM CoQ10 could protect buck spermatozoa from cryoinjury.