Liu Yundie, Cai Hui, Guo Xinrui, Aierken Aili, Hua Jinlian, Ma Baohua, Peng Sha
College of Veterinary Medicine, Shaanxi Centre of Stem Cells Engineering & Technology, Northwest Agriculture and Forestry University of Science and Technology, Yangling, 712100, Shaanxi, China.
Stress Biol. 2022 Nov 14;2(1):47. doi: 10.1007/s44154-022-00068-9.
Current measures mainly focus on how melatonin reduces physiological heat stress in animals, but its effects on reproductive damage to male dairy goats have been neglected. This study aimed to determine the protective effect of melatonin on male reproduction during heat stress in dairy goats and to further explore its mechanisms. A natural heat stress model of Saanen dairy goats was used to assess testicular tissue damage 7 days after heat stress and to examine semen quality changes during a spermatogenic cycle. RNA-seq, Western blot, RT-qPCR, and immunofluorescence staining were used to explore the mechanism by which melatonin protects against heat stress-induced reproductive damage and to validate the results. The data suggested that melatonin significantly alleviated the heat stress-induced decrease in sperm quality, protected varicose tubule structure, reduced the levels of heat shock proteins and apoptotic proteins and protected the spermatocytes and round spermatozoa, which are mainly affected by heat stress. RNA-seq results suggest that melatonin inhibits the PI3K/AKT signaling pathway, reduces the level of p-AKT, and promotes elevated BCL-2. In addition, melatonin treatment could upregulate the gene expression of MT2 which was downregulated by heat stress and improve the change in extracellular matrix components and restore serum testosterone levels. Our results suggest that melatonin can protect against testicular and spermatogenic cell damage and improve semen quality in male dairy goats under heat stress. This study provides an important reference for subsequent studies on the molecular mechanisms of melatonin in protecting male reproductive processes under heat stress and using exogenous melatonin to prevent heat stress.
目前的措施主要集中在褪黑素如何减轻动物的生理热应激，但它对雄性奶山羊生殖损伤的影响却被忽视了。本研究旨在确定褪黑素对奶山羊热应激期间雄性生殖的保护作用，并进一步探索其机制。采用萨能奶山羊自然热应激模型，评估热应激7天后睾丸组织损伤情况，并检测生精周期内精液质量变化。运用RNA测序、蛋白质免疫印迹法、逆转录定量聚合酶链反应和免疫荧光染色等方法，探索褪黑素保护免受热应激诱导的生殖损伤的机制并验证结果。数据表明，褪黑素显著减轻了热应激诱导的精子质量下降，保护了曲张小管结构，降低了热休克蛋白和凋亡蛋白水平，并保护了主要受影响的精母细胞和圆形精子。RNA测序结果表明，褪黑素抑制PI3K/AKT信号通路，降低p-AKT水平，并促进BCL-2水平升高。此外，褪黑素处理可上调热应激下调的MT2基因表达，改善细胞外基质成分变化，并恢复血清睾酮水平。我们的结果表明，褪黑素可以保护睾丸和生精细胞免受损伤，并提高热应激下雄性奶山羊的精液质量。本研究为后续关于褪黑素在热应激下保护雄性生殖过程的分子机制以及使用外源性褪黑素预防热应激的研究提供了重要参考。
