Effect of Duxiao Ganqing Pill on liver inflammation in rats with cirrhotic endotoxemia: An analysis based on the TLR4/MyD88/NF-κB signaling pathway

Objective To establish a rat model of cirrhotic endotoxemia by CCl4 compound modeling, and to investigate the protective mechanism of Duxiao Ganqing Pill against liver inflammatory injury. Methods A total of 66 rats were selected, among which 17 died during modeling. Among the remaining 49 rats, 3 were selected to measure endotoxin and observe liver structure to determine whether the model was successfully established, and the other 46 rats were randomly divided into normal group with 6 rats, model group with 8 rats, lactulose group with 8 rats, and high-, middle-, and low-dose Duxiao Ganqing Pill ( 223. 4, 111. 7, and 58. 9 mg/kg) groups with 8 rats in each group. CCl4 compound modeling was performed for 8 weeks to establish a rat model of liver cirrhosis. The rats in the normal group and the model group were given distilled water, those in the lactulose group were given lactulose, and those in the Duxiao Ganqing Pill groups were given the drug according to the above doses, once a day for 2 consecutive months. The change in the content of endotoxin was measured. HE staining was used to observe the change in liver tissue, ELISA was used to measure the content of tumor necrosis factor-α ( TNF-α) , interleukin-1β ( IL-1β) , and interleukin-6 ( IL-6) in liver tissue, and Western blot and RT-PCR were used to measure the protein and mRNA expression of TLR4, MyD88, and NF-κB. A one-way analysis of variance was used for data comparison between groups, and the least significant difference t-test was used for further comparison of data with homogeneity of variance between two groups. Results There was a significant difference in serum endotoxin level between these groups ( F = 26. 011, P < 0. 001) ; the model group had a signifi-cantly higher endotoxin level than the normal group ( P < 0. 01) ; after treatment, the lactulose group and high-, middle-, and low-dose Duxiao Ganqing Pill groups had significantly lower serum endotoxin levels than the model group ( P < 0. 01) . There were significant differences in serum levels of IL-6, IL-1β, and TNF-α between these groups ( F = 35. 390, P = 0. 002; F = 38. 271, P = 0. 001; F =40. 241, P < 0. 001) ; the model group had significantly higher serum levels of IL-6, IL-1β, and TNF-α than the normal group ( all P < 0. 01) ; after treatment, the lactulose group and high-, middle-, and low-dose Duxiao Ganqing Pill groups had significantly lower serum levels of IL-6, IL-1β, and TNF-α than the model group ( all P < 0. 01) . There were significant differences in the mRNA and protein expression of TLR4, MyD88, and NF-κB in liver tissue between these groups ( F = 24. 483, 29. 547, 19. 242, 18. 752, 22. 146, and 15. 834, all P < 0. 01) ; the model group had significantly higher mRNA and protein expression of TLR4, MyD88, and NF-κB in liver tissue than the normal group ( all P < 0. 01) ; after treatment, the lactulose group and high-, middle-, and low-dose Duxiao Ganqing Pill groups showed significant reductions in the mRNA and protein expression of TLR4, MyD88, and NF-κB in liver tissue ( all P < 0. 01) , and the middle-and high-dose Duxiao Ganqing Pill groups had significantly greater reductions than the low-dose Duxiao Ganqing Pill group ( all P < 0. 01) . Conclusion Duxiao Ganqing Pill can inhibit the transduction of inflammatory signals by downregulating the TLR4/MyD88/NF-κB signaling pathway in liver tissue, reduce the expression of the cytokines TNF-α, IL-1β, and IL-6, and thus alleviate endotoxemia and exert a protective effect on liver tissue.