Department of Medical Biosciences, University of the Western Cape, Bellville 7535, South Africa.
Asian J Androl. 2011 Jan;13(1):43-52. doi: 10.1038/aja.2010.76. Epub 2010 Nov 15.
Spermatozoa are constantly exposed to the interphase between oxidation through high amounts of reactive oxygen species (ROS) and leukocytes, and reduction by means of scavengers and antioxidants. Considering the very special functions as being the only cells with such high polarization and exerting their functions outside the body, even in a different individual, the female genital tract, the membranes of these cells are chemically composed of an extraordinary high amount of polyunsaturated fatty acids. This in turn, renders them very susceptible to oxidative stress, which is defined as an imbalance between oxidation and reduction towards the oxidative status. As a result, ROS deriving from both leukocytes and the male germ cells themselves cause a process called 'lipid peroxidation' and other damages to the sperm cell. On the other hand, a certain limited amount of ROS is essential in order to trigger vital physiological reactions in cells, including capacitation or the acrosome reaction in sperm. The treatment of patients with antioxidants to compensate the oxidative status caused by oxidative stress is highly debated as uncontrolled antioxidative treatment might derail the system towards the reduced status, which is also unphysiological and can even induce cancer. This paradox is called the 'antioxidant paradox'. Therefore, a proper andrological diagnostic work-up, including the evaluation of ROS levels and the antioxidant capacity of the semen, has to be carried out beforehand, aimed at keeping the fine balance between oxidation and scavenging of vital amounts of ROS.
精子不断受到氧化的影响，通过大量的活性氧物质（ROS）和白细胞，以及通过清除剂和抗氧化剂进行还原。考虑到其非常特殊的功能，即作为唯一具有如此高极化程度并在体外发挥功能的细胞，甚至在不同个体的女性生殖道中，这些细胞的膜化学组成中含有极高比例的多不饱和脂肪酸。这反过来又使它们非常容易受到氧化应激的影响，氧化应激被定义为氧化和还原之间的不平衡向氧化状态的转变。结果，来自白细胞和男性生殖细胞本身的 ROS 引起了一种称为“脂质过氧化”的过程，并对精子细胞造成其他损害。另一方面，为了触发细胞中的重要生理反应，包括精子的获能或顶体反应，一定数量的 ROS 是必不可少的。用抗氧化剂治疗来补偿氧化应激引起的氧化状态的做法存在很大争议，因为不受控制的抗氧化治疗可能会使系统向还原状态偏离，这也是非生理的，甚至可能导致癌症。这种矛盾被称为“抗氧化悖论”。因此，必须事先进行适当的男科诊断工作，包括评估 ROS 水平和精液的抗氧化能力，旨在保持氧化和清除重要数量的 ROS 之间的微妙平衡。
