Effects of sildenafil on the proliferation of Caco-2 cells and inflammatory response in NCM460 cells

To investigate the inhibitory effect of sildenafil on Caco-2 cell proliferation and its anti-inflammatory effect on menadione-induced NCM460 cell inflammation model, MTT assay was used to determine cell proliferation. Intracellular reactive oxygen species(ROS)and nitric oxide(NO)levels were detected by fluorescent probe. Western blot was used to detect the expression of eNOS/ERK/JNK pathway related proteins in Caco-2 cells and correlated inflammatory cytokines in NCM460 cells. The effect of sildenafil on the growth of two probiotics was determined by spectrophotometry. Results showed that sildenafil signi-ficantly inhibited the proliferation of Caco-2 cells and enhanced the expression levels of eNOS, p-eNOS, p-JNK1/2 and p-ERK1/2 proteins in Caco-2 cells; while after adding N^G-nitro-L-arginine methyl ester(L-NAME), the expression levels of eNOS, p-eNOS, p-JNK1/2 and p-ERK1/2 proteins were significantly lower than those of the sildenafil group. Compared with the menadione group, sildenafil significantly reduced ROS levels in NCM460 cells and inhibited the expression levels of IL-6, IL-1β, p62, and TNF-α. Moreover, high concentrations of sildenafil had no obvious toxic effects on Lactobacillus casei and Lactobacillus rhamnosus. Thus, the results indicated that sildenafil could effectively inhibit the intestinal inflammatory response without affecting the balance of the intestinal flora, and prevent colorectal cancer by reducing the oxidative stress responses in the intestinal cells.