Institute of Reproductive Medicine, Medical School, Nantong University, Nantong, Jiangsu, China.
Center of Reproductive Medicine, Department of Obstetrics and Gynecology, Affiliated Hospital of Nantong University, Nantong, Jiangsu, China.
Front Endocrinol (Lausanne). 2024 Aug 21;15:1432612. doi: 10.3389/fendo.2024.1432612. eCollection 2024.
Epididymal lumen fluids provides a stable microenvironment for sperm maturation. Ca binding protein CABS1 is known to maintain structural integrity of mouse sperm flagella during epididymal transit of sperm. Besides, CABS1 was reported to contain anti-inflammatory peptide sequences and be present in both human saliva and plasma. However, little is known about the role of CABS1 in regulation of the microenvironment of epididymal lumen fluids.
To further confirm the role of CABS1 in epididymis, we identified the expression of CABS1 in epididymal lumen fluids. Moreover, high performance liquid chromatography, coupled with tandem mass spectrometry technique was used to analyze the metabolic profiles and microperfusion of the cauda epididymis and inductively coupled plasma mass spectrometry (ICP-MS) assays was used to detect the concentration of metal ion of mouse cauda epididymal lumen fluids in CABS1 deficient and normal mice.
The results showed that CABS1 is present in epididymal lumen fluids, and the concentration of calcium in epididymal lumen fluids is not changed in male mice. Among 34 differential metabolites identified in cauda epididymis, 21 were significantly upregulated while 13 were significantly downregulated in KO cauda epididymis. Pathway analysis identified pyrimidine metabolism, inositol phosphate metabolism, arachidonic acid metabolism, purine metabolism and histidine metabolism as relevant pathways in cauda epididymis.
The perturbations of mitochondrial dysfunction and inflammation may be the crucial reason for the poor performance of sperm.
附睾管腔液为精子成熟提供了稳定的微环境。已知钙结合蛋白 CABS1 在精子通过附睾的过程中维持精子鞭毛的结构完整性。此外，CABS1 被报道含有抗炎肽序列，存在于人类唾液和血浆中。然而，CABS1 在调节附睾管腔液微环境中的作用知之甚少。
为了进一步证实 CABS1 在附睾中的作用，我们鉴定了 CABS1 在附睾管腔液中的表达。此外，采用高效液相色谱-串联质谱技术分析了附睾尾的代谢谱和微灌流，电感耦合等离子体质谱（ICP-MS）检测了 CABS1 缺失和正常小鼠附睾尾管腔液中金属离子的浓度。
结果表明 CABS1 存在于附睾管腔液中，且雄性小鼠附睾管腔液中钙浓度不变。在鉴定的 34 种差异代谢物中，21 种在 KO 附睾尾中显著上调，13 种显著下调。通路分析确定嘧啶代谢、肌醇磷酸盐代谢、花生四烯酸代谢、嘌呤代谢和组氨酸代谢是附睾尾相关通路。
线粒体功能障碍和炎症的失调可能是精子表现不佳的关键原因。
