Effects of rhynchophylline and isorhynchophylline on nitric oxide and endothelin-1 secretion from RIMECs induced by Listeriolysin O in vitro

To investigate the effects of Listeriolysin O (LLO) on morphology, nitric oxide (NO) and endothelin-1 (ET-1) release by rat intestinal microvascular endothelial cells (RIMECs). We aimed to elucidate a preliminary therapeutic mechanism of action of rhynchophylline and isorhynchophylline (active components of Uncaria rhynchophylla) on listeriosis treatment and how they regulate the LLO-induced parasecretion of vasoactive agents in RIMECs. A RIMECs injury model was established by stimulating the cells with different concentrations of LLO. Compared with NC, LLO stimulation caused a dose-dependent decrease in RIMECs viability. After 12 h, the levels of secreted NO and ET-1 were higher than NC and the ratio of NO:ET-1 decreased. The mRNA expression results of iNOS and ET-1 mRNA show the same trend. These deleterious effects could be partially reversed by the addition of rhynchophylline and isorhynchophylline at the same time as LLO. By preventing the morphological changes, decreasing cell death, and preventing disordered NO and ET-1 production in RIMECs induced by LLO, rhynchophylline and isorhynchophylline may help improve therapy for listeriosis.