The regulatory effect of oxymatrine on the TLR4/MyD88/NF-κB signaling pathway in lipopolysaccharide-induced MS1 cells

Background: Oxymatrine (OM), a major quinolizidine alkaloid extracted from the roots of Sophora flavescens, has been proved to regulate a variety of signaling pathways to produce a wide range of pharmacological effects. Objectives: The regulatory effects of OM on the TLR4/MyD88/NF-kappa B signaling pathway under the stimulation of lipopolysaccharide (LPS) in MS1 cells were explored to illuminate the potential anti-inflammatory mechanism of OM for pancreatitis treatment. Methods: The signaling molecules related to the TLR4/MyD88/NF-kappa B pathway in MS1 cells were detected by Western blotting under different conditions, including OM pretreatment and LPS stimulation. The mRNA expression levels of TLR4, MyD88, NF-kappa B p65 and I kappa B alpha were detected by real-time PCR. The NF-kappa B p65 nuclear translocation in MS1 cells was measured by immunofluorescence, and the pro-inflammatory cytokine of IL-1 beta was detected by ELISA. Results: Increased levels of TLR4, MyD88 and NF-kappa B p65, induced by LPS stimulation, were significantly inhibited by OM pretreatment in MS1 cells. The decreased protein, but not mRNA, level of I kappa B alpha induced by LPS stimulation was increased by OM pretreatment. Meanwhile, LPS induced NF-kappa B p65 protein translocation to the nucleus as well as LPS increased expression of IL-1 beta were also inhibited by OM pretreatment. Conclusion: Inhibitory effects of OM on molecules related to the TLR4/MyD88/NF-kappa B signaling pathway in pancreatic microvascular endothelial cells can alleviate inflammatory responses.