Urology Research Laboratory, H6.47, McGill University Health Centre at Royal Victoria Hospital, 687 Ave des Pins ouest, Montréal, QC, Canada H3A 1A1.
Hum Reprod. 2010 Jul;25(7):1619-30. doi: 10.1093/humrep/deq110. Epub 2010 May 24.
Semenogelin (Sg), the main protein of human semen coagulum, prevents sperm capacitation. The objective of this study was to examine the role of Sg and its mechanism of action.
Sg blocked sperm capacitation triggered by various stimuli, via inhibition of superoxide anion (O(2)-; luminescence assay) and nitric oxide (NO; tested using diaminofluorescein) generation. Triton-soluble and -insoluble sperm fractions contained Sg and Sg peptides (immunoblotting), the level of which decreased with initiation of capacitation. This drop was prevented by superoxide dismutase and NO* synthase inhibitor and was reproduced by addition of O(2)- and NO. Zinc (Zn(2+)) blocked and a zinc chelator (TPEN) promoted the decline in Sg levels. There was a decreased labelling of Sg on the head in capacitating spermatozoa with the two fixation techniques tested (immunocytochemistry). Reactive oxygen species (ROS) (O(2)- and NO) caused, these changes, and zinc prevented them. Spermatozoa quickly internalized Sg upon incubation and Sg was then rapidly degraded in a zinc-inhibitable manner.
Sg blocked capacitation mainly via inhibition of ROS generation. Spermatozoa appeared permeable to Sg and processed Sg in a zinc-inhibitable fashion. ROS themselves could promote sperm disposal of Sg which maybe one of the mechanisms that allows initiation of capacitation.
精浆素（Sg）是人类精液凝块的主要蛋白质，可防止精子获能。本研究旨在探讨 Sg 的作用及其作用机制。
Sg 通过抑制超氧阴离子（O(2)-；发光测定法）和一氧化氮（NO；使用二氨基荧光素检测）的产生，阻断各种刺激引发的精子获能。Triton 可溶和不可溶精子部分含有 Sg 和 Sg 肽（免疫印迹），其水平随着获能的开始而降低。这种下降可被超氧化物歧化酶和一氧化氮合酶抑制剂预防，并可通过添加 O(2)-和 NO来重现。锌（Zn(2+））阻断，锌螯合剂（TPEN）促进 Sg 水平下降。用两种测试的固定技术（免疫细胞化学）检测到获能精子头部 Sg 的标记减少。活性氧（ROS）（O(2)-和 NO）引起这些变化，而锌则阻止了这些变化。精子在孵育过程中迅速内化 Sg，随后 Sg 以锌抑制的方式迅速降解。
Sg 主要通过抑制 ROS 生成来阻断获能。精子似乎对 Sg 具有通透性，并以锌抑制的方式处理 Sg。ROS 本身可以促进精子对 Sg 的处理，这可能是允许获能开始的机制之一。
