Abstract: PURPOSE: To study the expression of miR-146a in saliva of chronic periodontitis patients and its influence on gingival crevicular inflammation and MMP-8/TIMP-1 levels. METHODS: Sixty-eight patients with chronic periodontitis treated in our hospital during March 2015 to January 2017 were chosen as the experimental group, while 50 healthy volunteers for physical examination were chosen as the control group. The level of miR-146a in saliva and inflammatory factors, MMP-8/TIMP-1 in gingival crevicular fluid were detected. Pearson test was used to assess the correlation between expression of miR-146a in saliva and the severity of disease with SPSS24.0 software package. RESULTS: The expression of miR-146a in saliva in the experimental group was significantly higher than that in the control group(P<0.05). The level of inflammatory cytokines (IL-1β, IL-6 and IL- 35, TNF-α), the indexes of periodontal clinical symptoms (PD, AL, PLI, BI) in the experimental group were significantly higher than those in the control group (P <0.05); and MMP-8 and TIMP-1 in gingival crevicular fluid in the experimental group were significantly higher than those in the control group(P<0.05). Pearson test found that the expression of miR-146a in saliva of patients with chronic periodontitis was positively correlated with the degree of gingival inflammation, the severity of periodontal symptoms and the level of MMP-8/TIMP-1. CONCLUSIONS: The expression of miR-146a in saliva of chronic periodontitis patients is abnormally high, and the specific expression is consistent with the degree of gingival inflammation and periodontal injury.

Key words: Chronic periodontitis, miR-146a, Gingival sulcus inflammation, MMP-8/TIMP-1