Protective Effects of Aqueous Extract of Radix Isatidis on Lipopolysaccharide-Induced Sepsis in C57BL/6J Mice

Endotoxic shock exhibits a considerably high mortality risk. It is defined as a systemic inflammatory response syndrome caused by a microbial infection. Radix Isatidis has anti-inflammatory, antiviral, and antipyretic effects and is used worldwide. This study investigated the antiendotoxin sepsis effects of an aqueous R. Isatidis extract (RIE) and explored the possible pharmacological molecular mechanisms. Male C57BL/6J mice were intravenously injected with 15 mg/kg lipopolysaccharide (LPS) to induce endotoxic shock. The results demonstrated that the survival rate of mice pretreated with RIE increased, and LPS-induced liver and lung damage were reduced by inhibiting inflammation. For elucidating detailed molecular mechanisms, we focused on LPS-induced transcription factors: nuclear factor-κB (NF-κB) and interferon regulatory factor 3 (IRF3). Our results demonstrated that the protective effects of RIE were strongly dependent on IRF3-induced interferon-β, not on NF-κB-induced tumor necrosis factor-α and interleukin-1β. In addition, RIE suppressed the phosphorylation of IRF3, not NF-κB. In conclusion, this study revealed the antiendotoxic properties of RIE on LPS-induced sepsis and provided mechanistic evidence for the beneficial effects of RIE.