Fujii Junichi, Iuchi Yoshihito, Matsuki Shingo, Ishii Tatsuya
Department of Biochemistry, Yamagata University School of Medicine, 2-2-2 Iidanishi, Yamagata 990 9585, Japan.
Asian J Androl. 2003 Sep;5(3):231-42.
Reactive oxygen species (ROS) are produced under oxidative stress, such as high oxygen concentration and during the metabolic consumption of oxygen molecules. Male reproductive tissues appear to be continuously exposed to ROS produced by active metabolism. In addition, spermatozoa must pass through a high oxygen environment during the mating process. Thus, to maintain viable reproductive ability, a protective mechanism against oxidative stress is of importance. Here, we overview our current understanding of the cooperative function of antioxidative and redox systems that are involved in male fertility. Superoxide dismutase and glutathione peroxidase are major enzymes that scavenge harmful ROS in male reproductive organs. In turn, glutathione and thioredoxin systems constitute the main redox systems that repair oxidized and damaged molecules and also play a role in regulating a variety of cellular functions. While glutathione functions as an antioxidant by donating electrons to glutathione peroxidase and thioredoxin donates electrons to peroxiredoxin as a counterpart of glutathione peroxidase. In addition, aldo-keto reductases, which detoxify carbonyl compounds produced by oxidative stress, are present at high levels in the epithelia of the genital tract and Sertoli cells of the testis. Since these systems are involved in cross-talk, a comprehensive understanding will be required to maintain the physiological functions of male reproductive system.
活性氧（ROS）在氧化应激条件下产生，如高氧浓度以及氧分子的代谢消耗过程中。雄性生殖组织似乎持续暴露于由活跃代谢产生的ROS中。此外，精子在交配过程中必须穿过高氧环境。因此，为维持可行的生殖能力，对抗氧化应激的保护机制至关重要。在此，我们概述目前对参与雄性生育的抗氧化和氧化还原系统协同功能的理解。超氧化物歧化酶和谷胱甘肽过氧化物酶是清除雄性生殖器官中有害ROS的主要酶。反过来，谷胱甘肽和硫氧还蛋白系统构成主要的氧化还原系统，它们修复氧化和受损分子，并在调节多种细胞功能中发挥作用。谷胱甘肽通过向谷胱甘肽过氧化物酶提供电子而作为抗氧化剂发挥作用，硫氧还蛋白则作为谷胱甘肽过氧化物酶的对应物向过氧化物还原酶提供电子。此外，使氧化应激产生的羰基化合物解毒的醛酮还原酶在生殖道上皮和睾丸支持细胞中高水平存在。由于这些系统相互关联，需要全面了解以维持雄性生殖系统的生理功能。
