Ezz Mohamed Aboul, Montasser Abd Elmonem, Hussein Mamdouh, Eldesouky Ashraf, Badr Magdy, Hegab Abd Elraouf, Balboula Ahmed, Zaabel Samy M
Department of Theriogenology, Faculty of Veterinary Medicine, Mansoura University, 35516, Egypt.
Artificial Insemination and Embryo Transfer Department, Animal Reproduction Research Institute (ARRI), Al Haram, Giza, Egypt.
Reprod Biol. 2017 Mar;17(1):42-50. doi: 10.1016/j.repbio.2016.12.001. Epub 2016 Dec 29.
The cryopreservation of germ cells is a major tool for the propagation of animals with desired genetic traits. Although cryopreservation of spermatozoa in some animals is effective, its effectiveness is variable. For example, cryopreservation efficiency of buffalo bull spermatozoa remains very poor. In this study, we evaluated sperm DNA damage and ultrastructure in buffalo bull spermatozoa vitrified in the presence or absence of cholesterol-loaded cyclodextrins (CLC). Our results showed that cryopreserved buffalo spermatozoa had elevated levels of deteriorated plasma and mitochondrial membranes, which are the likely causes of DNA damage after vitrification. Accordingly, the levels of the activity of Alanine Aminotransferase (ALT), Alkaline phosphatase (ALP) and Aspartate Aminotransferase (AST) were also elevated following exposure of buffalo bull spermatozoa to a cycle of freezing-thawing. Importantly, supplementation of Tris-Egg Yolk-Glucose (TEYG) extender with (CLC) improved the quality of buffalo spermatozoa following cryopreservation. This protective effect of CLC is likely due to decreasing mitochondrial and plasma membrane deterioration with subsequent inhibition of DNA damage. These results suggest that cholesterol loss is the likely reason for poor semen quality in buffaloes following cryopreservation, and provide evidence that manipulating lipid content during cryopreservation is a promising strategy to improve the quality of buffalo semen.
生殖细胞的冷冻保存是繁殖具有所需遗传特征动物的主要手段。虽然某些动物精子的冷冻保存是有效的，但其效果存在差异。例如，水牛公牛精子的冷冻保存效率仍然很低。在本研究中，我们评估了在有或没有胆固醇负载环糊精（CLC）的情况下玻璃化的水牛公牛精子中的精子DNA损伤和超微结构。我们的结果表明，冷冻保存的水牛精子中质膜和线粒体膜的退化水平升高，这可能是玻璃化后DNA损伤的原因。因此，水牛公牛精子经历一轮冻融后，丙氨酸转氨酶（ALT）、碱性磷酸酶（ALP）和天冬氨酸转氨酶（AST）的活性水平也升高。重要的是，用（CLC）补充Tris-蛋黄-葡萄糖（TEYG）稀释液可提高冷冻保存后水牛精子的质量。CLC的这种保护作用可能是由于减少了线粒体和质膜的退化，从而抑制了DNA损伤。这些结果表明，胆固醇流失可能是水牛冷冻保存后精液质量差的原因，并提供了证据表明在冷冻保存过程中控制脂质含量是提高水牛精液质量的一种有前景的策略。
