Ameliorative Effect and Mechanism of Chinese Yam DP1 on Sexual Function in Naturally Aging Rats

Objective: Investigating the ameliorative effect and mechanism of Chinese yam protein DP1 on aging-related male sexual dysfunction in rats. Methods: In the in vivo experiment, 2-month-old male SD rats served as the control group, while 15-month-old male SD rats were randomly divided into model group, low-, medium-, and high-dose DP1 groups (0.25, 0.5, and 1 mg/kg), with continuous intragastric administration for 4 months. In the in vitro experiments, a co-culture system of primary mouse cavernous endothelial cells (MCECs) and primary mouse cavernous smooth muscle cells (MCSMCs) was established using a Transwell chamber. Hydrogen peroxide (H₂O₂) was used to induce injury, followed by treatment with 250 μg/mL DP1. Results: DP1 significantly increased the number of erections, captures, and mating behaviors in naturally aging rats (P<0.05), shortened erection latency and capture latency (P<0.05), repaired corpus cavernosum tissue morphology, increased nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) levels (P<0.05), and upregulated the protein expression levels of phosphorylated phosphatidylinositol 3 kinase (p-PI3K)/PI3K, phosphorylated protein kinase B (p-Akt)/Akt, and phosphorylated endothelial nitric oxide synthase (p-eNOS)/eNOS (P<0.05). In the in vitro model, DP1 significantly increased cell viability (P<0.05), elevated NO and cGMP levels (P<0.05), decreased Ca²⁺ concentration (P<0.05), and upregulated p-PI3K/PI3K, p-Akt/Akt and p-eNOS/eNOS protein expression levels (P<0.05). Conclusion: DP1 improved sexual function in naturally aging rats, and the mechanism might be related to repairing the interaction between endothelial cells and smooth muscle cells and activating the NO/cGMP signaling pathway.