Laboratory of Seminology - Sperm Bank "Loredana Gandini", Department of Experimental Medicine, University of Rome "La Sapienza", Rome, Italy.
Adv Exp Med Biol. 2019;1166:149-167. doi: 10.1007/978-3-030-21664-1_9.
Cryopreservation is a technique that can keep sperm alive indefinitely, enabling the conservation of male fertility. It involves the cooling of semen samples and their storage at -196 °C in liquid nitrogen. At this temperature all metabolic processes are arrested. Sperm cryopreservation is of fundamental importance for patients undergoing medical or surgical treatments that could induce sterility, such as cancer patients about to undergo genotoxic chemotherapy or radiotherapy, as it offers these patients not only the hope of future fertility but also psychological support in dealing with the various stages of the treatment protocols.Despite its importance for assisted reproduction technology (ART) and its success in terms of babies born, this procedure can cause cell damage and impaired sperm function. Various studies have evaluated the impact of cryopreservation on chromatin structure, albeit with contradictory results. Some, but not all, authors found significant sperm DNA damage after cryopreservation. However, studies attempting to explain the mechanisms involved in the aetiology of cryopreservation-induced DNA damage are still limited. Some reported an increase in sperm with activated caspases after cryopreservation, while others found an increase in the percentage of oxidative DNA damage. There is still little and contradictory information on the mechanism of the generation of DNA fragmentation after cryopreservation. A number of defensive strategies against cryoinjuries have been proposed in the last decade. Most studies focused on supplementing cryoprotectant medium with various antioxidant molecules, all aimed at minimising oxidative damage and thus improving sperm recovery. Despite the promising results, identification of the ideal antioxidant treatment method is still hampered by the heterogeneity of the studies, which describe the use of different antioxidant regimens at different concentrations or in different combinations. For this reason, additional studies are needed to further investigate the use of antioxidants, individually and in combination, in the cryopreservation of human sperm, to determine the most beneficial conditions for optimal sperm recovery and preservation of fertility.
冷冻保存是一种可以使精子无限期存活的技术，能够保存男性的生育能力。它涉及到精液样本的冷却，以及将其储存在-196°C的液氮中。在这个温度下，所有的代谢过程都停止了。精子冷冻保存对于接受可能导致不育的医学或手术治疗的患者至关重要，例如即将接受致育性化疗或放疗的癌症患者，因为它不仅为这些患者提供了未来生育的希望，而且在处理治疗方案的各个阶段时也提供了心理支持。
尽管冷冻保存对辅助生殖技术（ART）非常重要，并且在出生婴儿方面取得了成功，但它也会导致细胞损伤和精子功能受损。尽管有一些研究评估了冷冻保存对染色质结构的影响，但结果却相互矛盾。一些作者但不是所有作者都发现冷冻保存后精子 DNA 损伤显著。然而，试图解释冷冻保存引起的 DNA 损伤发病机制的研究仍然有限。一些作者报告说冷冻保存后精子中的激活半胱天冬酶增加，而另一些作者则发现氧化 DNA 损伤的百分比增加。关于冷冻保存后 DNA 碎片化产生的机制，目前仍缺乏信息，且信息相互矛盾。
在过去的十年中，已经提出了许多针对冷冻损伤的防御策略。大多数研究都集中在通过添加各种抗氧化分子来补充冷冻保护剂培养基上，目的都是为了最大程度地减少氧化损伤，从而提高精子的回收率。尽管结果很有希望，但由于研究的异质性，仍难以确定理想的抗氧化治疗方法，这些研究描述了在不同浓度或不同组合下使用不同的抗氧化方案。因此，需要进行更多的研究来进一步探讨抗氧化剂的单独使用和联合使用在人类精子冷冻保存中的应用，以确定最有利于最佳精子回收和保持生育力的条件。
