Abstract：
Melatonin, a hormone synthesized in various tissues, plays a crucial role in modulating sperm characteristics, yet its protective function on boar sperm remains poorly understood. This study aimed to investigate the expression and localization of melatonin-related proteins (AANAT, ASMT, MT1, MT2, and NQO2) in pig tissues, assess the impact of melatonin on pig sperm motility parameters and quality, and elucidate the underlying molecular mechanisms. Our results revealed widespread expression of AANAT, ASMT, MT1, MT2, and NQO2 proteins in pig tissues, particularly in the testis. Specific localization patterns were observed in Leydig cells, reproductive epithelium, and columnar epithelium cells in the testis and cauda epididymis. Additionally, melatonin membrane receptors MT1 and MT2 were detected in boar sperm. Melatonin treatment significantly enhanced boar sperm motility parameters and quality, particularly with 10 nM melatonin treatment. Inhibition of the MT1 receptor, but not the MT2 receptor, resulted in decreased sperm motility, highlighting the pivotal role of the MT1 receptor in mediating melatonin\'s effects on boar sperm. Metabolomic analysis revealed significant alterations in sperm metabolites following melatonin supplementation, particularly in amino acid metabolism. Overall, our findings provide comprehensive insights into melatonin\'s mechanisms in improving boar sperm quality, suggesting its potential as a therapeutic agent for enhancing male fertility.
摘要：
褪黑激素,一种在各种组织中合成的激素，在调节精子特性中起着至关重要的作用，然而，它对公猪精子的保护功能仍然知之甚少。本研究旨在探讨褪黑素相关蛋白(AANAT,ASMT,MT1，MT2和NQO2）在猪组织中，评估褪黑素对猪精子运动参数和质量的影响，并阐明潜在的分子机制。我们的结果揭示了AANAT的广泛表达，ASMT,猪组织中的MT1、MT2和NQO2蛋白，尤其是在睾丸中。在Leydig细胞中观察到特定的定位模式，生殖上皮，睾丸和附睾尾的柱状上皮细胞。此外,在公猪精子中检测到褪黑素膜受体MT1和MT2。褪黑素治疗显著提高公猪精子运动参数和质量，特别是10nM褪黑素治疗。抑制MT1受体，但不是MT2受体，导致精子活力下降，强调MT1受体在介导褪黑素对公猪精子的作用中的关键作用。代谢组学分析显示，补充褪黑素后精子代谢产物发生显著变化，特别是在氨基酸代谢中。总的来说,我们的研究结果为褪黑素改善公猪精子质量的机制提供了全面的见解，这表明它有可能成为提高男性生育能力的治疗剂.
