Abstract: Objective:To investigate the role of TLR4 in liver inflammation induced by chronic periodontitis in rats. Methods:Twenty-four male Wistar rats were randomly euqally divided into two groups. In the periodontitis group, 20 μL Pg-LPS (1 g/L) was injected into the first and second gingival furrow of the maxilla on both sides of the rats, once every other day, three times a week, for 6 weeks. The control group was not treated. 12 h after the last injection of Pg-LPS, rats were sacrificed and the maxilla and liver were extracted. Histological method was used to detect the inflammatory response of the liver. qRT-PCR and Western blotting were used to detect the expression of TLR4, TNF-α, and IL-6. Results:HE staining showed that the hepatic cord was disorganized in the liver tissue of rats with chronic periodontitis, infiltrated by inflammatory cells such as neutrophils, and a large number of liver cells presented vacuolar changes. qRT-PCR results showed that the expression levels of TLR4, TNF-α, and IL-6 in the liver of rats in the chronic periodontitis group were higher than those in the control group. Western blot result of TLR4 was consistent with the gene expression. Conclusion:TLR4 plays an important role in the inflammatory changes of liver induced by chronic periodontitis in rats.

Key words: chronic periodontitis, liver inflammation, Toll like receptor 4