Fermented Gynochthodes officinalis (F.C.How) Razafim. & B.Bremer alleviates diabetic erectile dysfunction by attenuating oxidative stress and regulating PI3K/Akt/eNOS pathway

Abstract

Ethnopharmacological relevance: As a traditional Chinese medicine, Gynochthodes officinalis (F.C.How) Razafim. & B.Bremer (G. officinalis) has been historically as tonics to treat impotence. Fermentation is an ancient processing method for traditional Chinese medicine. Whether fermentation affects the therapeutic effects of G. officinalis on diabetic erectile dysfunction has so far remained unknown.

Aims of the study: In this research, we aim to determine the effect of fermented or unfermented G. officinalis root extract on diabetes mellitus-induced erectile dysfunction (DMED) and the potential mechanisms.

Materials and methods: Candida sp. B5, Lactobacillus sp. Y5 and Lactobacillus sp. R2 are applied for the fermentation of G. officinalis. The optimum fermentation conditions of G. officinalis are investigated. Sprague-Dawley rats were used to establish a diabetic erectile dysfunction model, treated with different concentrations of fermented or unfermented G. officinalis, to compare the effect of fermented or unfermented G. officinalis on DMED and explore underlying mechanisms by assessment of intracavernous pressure, ELISA, Western blot, Masson's trichrome staining, and immunofluorescence. The corpus cavernosum smooth muscle cells (CCSMCs) and Schwann cells were isolated and used to investigate the effect of fermented or unfermented G. officinalis on hydrogen peroxide (H₂O₂)-induced apoptosis.

Results: The results reveal the optimum fermentation conditions of G. officinalis using Lactobacillus sp. Y5 were determined to be 35 °C, the ratio of solid to liquid 1:10, and six days of fermentation. The fermentation increases the abundance of major active ingredients within G. officinalis. After fermented or unfermented G. officinalis treatment for eight weeks by oral gavage at a dose of 100 mg kg^-1 or 300 mg kg^-1, the results show that the fermentation enhances the effect of G. officinalis on diabetic erectile dysfunction detected by intracavernous pressure. The protein expressions of the PI3K/Akt/eNOS pathway were upregulated in diabetic rats after fermented or unfermented G. officinalis treatment, while the level of oxidative stress was significantly reduced. Meanwhile, Masson's trichrome staining also displayed an improvement in the ratio of smooth muscle to collagen. In vitro experiments confirmed that fermented or unfermented G. officinalis protected CCSMCs and Schwann cells from apoptosis. In contrast, fermented G. officinalis showed a fortified protective effect over unfermented G. officinalis.

Conclusion: Our findings suggest that fermentation can increase the composition of main active ingredients in G. officinalis and enhance its role in diabetic erectile dysfunction. It augurs the potential therapeutic application of fermented G. officinalis well for treating diabetic erectile dysfunction.

Keywords: Diabetes mellitus; Erectile dysfunction; Fermentation; Gynochthodes officinalis (F.C.How) Razafim. & B.Bremer; Nitric oxide synthase; Oxidative stress.