Theriogenology Department, Faculty of Veterinary Medicine, Benha University, Egypt.
Department of Veterinary Science, University of Torino, Grugliasco, Italy.
Cryobiology. 2020 Aug;95:51-59. doi: 10.1016/j.cryobiol.2020.06.006. Epub 2020 Jun 17.
This study aimed to improve the quality of cryopreserved beef bull (Piedmontese) semen by incorporation of relaxin in diluted semen before cryopreservation procedures. Semen samples were collected from 4 proven fertile bulls, using artificial vagina, once per week for 8 consecutive weeks and pooled together then diluted with Bullxcell® extender, and supplemented with different concentrations of relaxin (0 (control), 25, 50 and 100 ng/ml) before cooling, equilibration and freezing procedures. Frozen semen was thawed and assessed for motility by Computer-Assisted Sperm Analysis and vitality parameters such as acrosome, plasma membrane and DNA integrities, apoptosis, mitochondrial membrane potential, mucus penetration and SOD activity. The developmental potential of bovine embryos produced in vitro by using relaxin-treated was also investigated. In the present study, 50 and 100 ng/ml relaxin incorporation in extended bull semen before cryopreservation induced a reduction of sperm motility immediately after thawing (0h), whereas, during long incubation periods (1-2 h), relaxin showed a significant positive effect on sperm quality by improving the sperm motility and velocity parameters. Interestingly, sperm vitality was improved by 25 and 100 ng/ml relaxin and the blastocyst developmental rate was significantly increased in the 25 ng/ml relaxin group compared with controls (52/118, 44.0% vs. 32/116, 27.6%, respectively). These findings suggest a potential use of relaxin at the doses tested in the present study as an additive in the cryopreservation media of bull semen to improve sperm quality.
本研究旨在通过在冷冻保存程序前将松弛素添加到稀释的精液中，来提高冷冻牛肉公牛（皮埃蒙特牛）精液的质量。从 4 头经过验证的可育公牛中，每周使用人工阴道收集一次精液，连续 8 周，然后将其混合在一起，用 Bullxcell®稀释液稀释，并在冷却、平衡和冷冻程序前添加不同浓度的松弛素（0（对照）、25、50 和 100ng/ml）。冷冻精液解冻后，通过计算机辅助精子分析评估活力，并评估顶体、质膜和 DNA 完整性、凋亡、线粒体膜电位、黏液穿透和 SOD 活性等活力参数。还研究了使用松弛素处理的体外生产的牛胚胎的发育潜力。在本研究中，在冷冻保存前将松弛素添加到扩展的公牛精液中，浓度为 50 和 100ng/ml，可立即降低解冻后精子的活力（0h），然而，在长时间孵育期间（1-2h），松弛素通过改善精子活力和速度参数，对精子质量产生了显著的积极影响。有趣的是，松弛素浓度为 25 和 100ng/ml 可提高精子活力，并且 25ng/ml 松弛素组的囊胚发育率明显高于对照组（52/118，44.0%比 32/116，27.6%）。这些发现表明，在本研究中测试的剂量下，松弛素作为公牛精液冷冻保存介质的添加剂，可能具有提高精子质量的潜在用途。
