The role of MMP-8 and MMP-9 in the pathogenesis of chronic periodontitis

Abstract

Introduction. The main pathogenetic aspect of the development and progression of inflammatory periodontal diseases is the imbalance of the microbiota of oral biotopes and the inflammatory response, one of the nonspecific components of which is the activation of matrix metalloproteinases. The aim of the study was to establish the role of matrix metalloproteases MMP-8 and MMP-9 in the pathogenesis of chronic periodontitis. Methods. The clinical material was the discharge of the periodontal pocket of patients with chronic periodontitis (54 samples) and with an intact periodontium (28 samples). Using ELISA, the content of matrix metalloproteases MMP-8 and MMP-9 was determined. Markers of periodontopathogenic bacteria were isolated using real-time PCR. Statistical data processing was carried out using the software package for statistical data processing STATA v.14 using nonparametric methods. Results. In the group of patients with chronic periodontitis, the levels of MMP-8 and MMP-9 were significantly higher than in individuals with intact periodontium (median 8.52 [7.45; 9.5] ng/ml versus 2.23 [0.843; 3.32], p < 0.001 and median 18.33 [16.32; 18.95] ng/ml versus 3.3 [2.13; 4.28], p < 0.001, respectively). In the majority (60.7%) of the examined control group, periodontopathogens were not isolated, while in all patients with chronic periodontitis, periodontopathogenic microflora was isolated. The most common were P. gingivalis, A. actinomycetemcomitans – periodontopathogenic bacteria of the first order, T. denticola – periodontopathogen of the second order, as well as their associations. The quantitative content of both metalloproteases MMP-8 and MMP-9 positively correlated with the isolation of P. gingivalis, A. actinomycetemcomitans, T. denticola, as well as periodontopathogen associations. No significant correlations were found in the examined group with intact periodontium. Conclusion. The activity of matrix metalloproteases MMP-8 and MMP-9 together with the action of proteolytic enzymes of periodontopathogens P. gingivalis, A. actinomycetemcomitans, T. denticola may reflect a synergistic effect aimed at the degradation of the extracellular matrix and leading to the destruction of periodontal tissues.