Zhu Zhendong, Umehara Takashi, Okazaki Tetsuji, Goto Masaaki, Fujita Yoko, Hoque S A Masudul, Kawai Tomoko, Zeng Wenxian, Shimada Masayuki
Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China.
Laboratory of Reproductive Endocrinology, Graduate School of Biosphere Science, Hiroshima University, Hiroshima, Japan.
Front Physiol. 2019 Mar 12;10:252. doi: 10.3389/fphys.2019.00252. eCollection 2019.
Sperm motility patterns are continuously changed after ejaculation to fertilization in the female tract. Hyperactivated motility is induced with high glucose medium or the oviduct fluids , whereas sperm maintain linear motility in the seminal plasma or the uterine fluids containing low glucose. Therefore, it is estimated that sperm motility patterns are dependent on the energy sources, and the mitochondrial oxidative phosphorylation is activated to produce ATP in low glucose condition. To elucidate these hypotheses, boar sperm was incubated in different energy conditions with the transcription and translation inhibitors . Sperm motility parameters, mitochondrial activity, ATP level, gene expression and protein synthesis were analyzed. Sperm progressive motility and straight-line velocity were significantly increased with decreasing glucose level in the incubation medium. Moreover, the mitochondrial protein turnover meaning transcription and translation from mitochondrial genome in sperm is activated during incubation. Incubation of sperm with mitochondrial translation inhibitor (D-chloramphenicol) suppressed mitochondrial protein synthesis, mitochondrial activity and ATP level in sperm and consequently reduced the linear motility speed, but not the motility. Thus, it is revealed that the mitochondrial central dogma is active in sperm, and the high-speed linear motility is induced in low glucose condition via activating the mitochondrial activity for ATP generation.
射精后至在雌性生殖道内受精的过程中，精子的运动模式会持续发生变化。高糖培养基或输卵管液可诱导精子产生超激活运动，而精子在精浆或含低糖的子宫液中保持直线运动。因此，据推测精子的运动模式取决于能量来源，并且在低糖条件下线粒体氧化磷酸化被激活以产生ATP。为了阐明这些假设，将公猪精子与转录和翻译抑制剂一起在不同能量条件下孵育。分析了精子运动参数、线粒体活性、ATP水平、基因表达和蛋白质合成。随着孵育培养基中葡萄糖水平的降低，精子的前向运动和直线速度显著增加。此外，精子中线粒体蛋白质更新，即线粒体基因组的转录和翻译，在孵育过程中被激活。用线粒体翻译抑制剂（D-氯霉素）孵育精子会抑制精子中线粒体蛋白质合成、线粒体活性和ATP水平，从而降低直线运动速度，但不影响运动性。因此，研究表明线粒体中心法则在精子中是活跃的，并且在低糖条件下通过激活线粒体产生ATP的活性诱导高速直线运动。
