Abstract: Objective　 To detect the contents of matrix metalloproteinase 9(MMP-9) in gingival groove fluid and serum of patients with chronic periodontitis (CP) and rheumatoid arthritis (RA), and discuss the correlation between MMP-9, CP and RA. Methods According to the inclusion criteria, 23 patients with rheumatoid arthritis (RA), 18 patients with chronic periodontitis (CP), 24 patients with chronic periodontitis and rheumatoid arthritis (CP+RA) and 16 healthy control group (H) were selected. The general conditions of patients were recorded, including the probing depth (PD), clinical attachment loss (CAL), sulcus bleeding index (SBI), simplified dental calculus index (CIS), and simplified debris index (DIS). Gingival crevicular fluid and serum were collected from each group. The expression level of MMP-9 in gingival crevicular fluid (GCF) and serum was detected by ELISA. The correlation between MMP-9 and periodontal index was analyzed. SPSS20.0 software package was used for statistical analysis of the data. Results The values of CAL, SBI and DI-S in RA+CP group were higher than RA group, CP group and H group. The level of MMP-9 in serum in CP+RA group (2671.71±1258.33μg/L) was higher than that in the RA group (1444.54±770.03μg/L), CP group (511.38±539.52μg/L), and H group (67.14±34.95μg/L) (P?0.05). The level of MMP-9 in the gingival crevicular fluid was higher in CP+RA group (26.11±5.25μg/L) than in the CP group (18.83±11.87μg/L) and H group (1.04±0.58μg/L) (P?0.05). There was a positive correlation between CAL and SBI in CP+RA group and MMP-9 expression in serum, CI-S and DI-S in CP group were positively correlated with serum MMP-9 . Conclusion There is a correlation between CP and RA, and the expression of MMP-9 significantly increases in CP and RA. MMP-9 may be related to the occurrence and development of CP and RA.

Key words: Porphyromonas gingivalis hemagglutinin 2, HA2, Porphyromonas gingivalis, Periodontitis