ABSTRACT
ObjectiveTo investigate the mechanism of action and main active components of Xiaoyaosan in the treatment of diabetic mellitus-induced erectile dysfunction （DMED）. MethodStreptozotocin （STZ） was used to induce a diabetic rat model. The therapeutic efficacy of Xiaoyaosan was evaluated by measuring intracavernous pressure/mean arterial pressure （ICP/MAP） and using Masson's trichrome staining. The main active components， key targets， and potential signaling pathways of Xiaoyaosan for the treatment of DMED were predicted by network pharmacology and molecular docking. The predicted results were then validated by in vitro and in vivo experiments. ResultThe ICP/MAP measurements and Masson's staining results showed that compared with the results in the control group， the erectile function of rats in the model group was significantly reduced （P<0.01）， and the ratio of smooth muscle/collagen fibers was significantly reduced （P<0.01）. After treatment with Xiaoyaosan， compared with the results in the model group， the ICP/MAP value of the diabetic rats was significantly elevated （P<0.01）， and the ratio of smooth muscle/collagen fibers was significantly higher （P<0.01）. The results of network pharmacology showed that Xiaoyaosan acted on key targets such as albumin （ALB）， protein kinase B1 （Akt1）， interleukin-6 （IL-6）， and tumor necrosis factor （TNF） through its main active components， including quercetin， kaempferol， β-sitosterol， and stigmasterol. These components were involved in the regulation of the advanced glycation end-products/receptor for advanced glycation end-products （AGE/RAGE） signaling pathway and the phosphoinositide 3-kinases（PI3K）/Akt signaling pathway in diabetic complications. The results of molecular docking showed that the key components of Xiaoyaosan had good binding capabilities with core targets， with β-sitosterol showing the strongest binding affinity with ALB. In vivo experiments demonstrated that Xiaoyaosan could significantly increase the protein and mRNA expression of ALB and Akt1 in serum， and inhibit the expression of IL-6 and TNF-α. It also significantly upregulated the expression of protein and mRNA of phosphorylation（p）-PI3K and p-Akt， and inhibited the RAGE expression. The results of cellular thermal shift assay （CETSA） showed that β-sitosterol could significantly inhibit the degradation of ALB protein. ConclusionXiaoyaosan may restore erectile function in diabetic rats by modulating targets such as ALB， Akt1， IL-6， and TNF， and through the RAGE/PI3K/Akt signaling pathway， and its main active component is likely β-sitosterol.