Abstract: This study investigated the repairing effect and underlying mechanism of peptides derived from Cucumaria frondosa tentacles peptides (CFTPs) on reproductive damage experimentally induced by cyclophosphamide (CTX) in male mice. The results demonstrated that CFTPs significantly regulated hormone levels in mice with CTX-induced reproductive injury, with the high-dose group exhibiting the most pronounced effects (P < 0.000 1). Following CFTPs intervention, the levels of testosterone and free testosterone in mice increased by 95% and 78%, respectively, while follicle-stimulating hormone and luteinizing hormone levels decreased by 33% and 37%, respectively. Furthermore, CFTPs improved erectile dysfunction by increasing nitric oxide levels and reducing phosphodiesterase-5 levels in penile tissues. Additionally, CFTPs alleviated oxidative stress by enhancing the activities of glutathione peroxidase and catalase, as well as the expression of proteins related to testosterone synthesis. CFTPs significantly increased the richness and diversity of the gut microbiota in mice, elevated the relative abundance of Bacteroidota and Firmicutes, and suppressed the proliferation of opportunistic pathogens such as Enterobacteriaceae, thereby reversing microbiota dysbiosis induced by CTX. Untargeted metabolomics showed that CFTPs regulated the arachidonic acid metabolic pathway through multiple targets, alleviated oxidative stress, restored hormonal balance and cell membrane stability, and ultimately enhanced the reproductive function of male mice. In conclusion, CFTPs have the potential to ameliorate reproductive damage in male mice, laying the foundation for the development of CFTPs as ingredients of functional foods to enhance reproductive health.

Key words: Cucumaria frondosa tentacles peptides; cyclophosphamide; reproductive damage; intestinal flora; untargeted metabolomics