Abstract:

Objective To discuss the anti-inflammatory and antioxidant effect of mesalazine （MSZ） in the RAW264.7 cell model，and to elucidate its therapeutic effect on periodontitis in the rats. Methods The proliferation rates of RAW264.7 cells stimulated by different concentrations （0， 62.5， 125.0， 250.0， 500.0， 1 000.0， and 2 000.0 mg·L^-1）of MSZ were detected by CCK-8 method to determine the optimal concentration of MSZ for cell treatment. Porphyromonas gingivalis lipopolysaccharide （P.g-LPS） and MSZ were used to treat the RAW264.7 cells， and the cells were divided into control group， P.g-LPS group， and MSZ+P.g-LPS group. The levels of reactive oxygen species （ROS） in the cells in various groups were detected by the DCFH-DA fluorescent probe assay； the malondialdehyde （MDA） levels， glutathione （GSH） levels and superoxide dismutase （SOD） activities in the cells in various groups were detected by ELISA method； the expression levels of inflammatory factors interleukin-8 （IL-8） and interleukin-1β （IL-1β） mRNA in the cells in various groups were detected by real-time fluorescence quantitative PCR （RT-qPCR） method.The periodontitis rat model was established by the ligation method combined with the injection of P.g bacterial fluid. A total of 18 rats were randomly divided into control group （without treatment）， model group （making periodontits model）， and drug administration group（making periodontits model and given MSZ）， and there were 6 rats in each group. Micro-CT was used to assess the alveolar bone destruction of the rats in various groups； HE staining was used to observe the morphology of periodontal tissue of the rats in various groups. Results Compared with control group， the proliferation rate of the cells in 500.0 mg·L^-1 MSZ group was significantly increased （P<0.01）， so 500.0 mg·L^-1 MSZ was subsequently selected to treat the cells. Compared with control group， the levels of ROS and MDA in the cells in P.g-LPS group were significantly increased （P<0.01）， and the level of GSH and activity of SOD were significantly decreased （P<0.01）， and the expression levels of IL-1β and IL-8 mRNA were significantly increased （P<0.01）； compared with P.g-LPS group， the levels of ROS and MDA in the cells in MSZ+P.g-LPS group were significantly decreased （P<0.01）， the level of GSH and activity of SOD were significantly increased （P<0.01）， and the expression levels of IL-1β and IL-8 mRNA were significantly decreased （P<0.01）. The micro-CT assay results showed that compared with control group， the distance from the cemento-enamel junction to alveolar bone crest （CEJ-ABC） of the rats in model group was significantly increased（P<0.01）， and the bone volume fraction （BV/TV） was significantly decreaced （P<0.05）； compared with model group； the CEJ-ABC of the rats in drug administration group was decreased（P<0.01）， and the BV/TV was increased （P<0.05）. The HE staining results showed that the inflammatory cell infiltration in periodontal tissue of the rats in drug administration group was reduced， and epithelial attachment was restored. Conclusion MSZ effectively inhibits the production of pro-inflammatory factors and peroxides in the P.g-LPS-induced RAW264.7 cells， improves the cellular anti-inflammatory and antioxidant capacity， inhibits the alveolar bone resorption， and alleviates the inflammation of periodontal tissues in the periodontitis rats.

Key words: Mesalazine, Porphyromonas gingivalis lipopolysaccharide, Periodontitis, Inflammatory factor, Oxidative stress