Intercellular junctions, proliferation, and apoptosis of the gingival epithelium in patients with periodontitis after laser therapy

Abstract

Introduction. E-cadherin participates in the formation of intercellular junctions and protects the epitheliocytes of the gums from apoptosis and regulates proliferation in them. The effect of a diode laser on intercellular contacts, proliferation, and apoptosis of gum epitheliocytes at various ages remains poorly studied. The purpose of the paper was to conduct a comparative analysis of the proliferative and apoptotic activity of human gingival epitheliocytes and their intercellular interaction in chronic inflammation, as well as in age-related diode laser therapy. Materials and methods.The study included patients with and without periodontal inflammation (30 patients in each group). The subjects were divided into 2 age groups: group I included patients aged 20–40 years, whereas group II – 41–60 years. Each age group was divided into subgroups: the control subgroup (patients without gingival inflammation); subgroup with periodontal inflammation (patients with chronic periodontitis); and subgroup after laser therapy (patients after therapy with 940-nm Prometey diode laser). We performed immunohistochemical studies using monoclonal antibodies to Ki-67, p53, E-cadherin; as well as computer morphometry and statistical data analysis. Results. Periodontitis combines a decrease in the number of both proliferating epitheliocytes and E-cadherin-positive intercellular contacts in the basal and spiny layers of the gum epithelium in both young and mature adults (p=0.00002). Exposure of a diode laser has a positive effect on the proliferative activity of epithelial cells and significantly increases the number of E-cadherin-positive intercellular contacts in the basal layer (p=0.00002), but does not affect the expression of p53 (p=0.9) in the gum epithelium in all age groups. Conclusion. Exposure of a diode laser increases the proliferation/apoptosis index in the gingival epithelium and brings the expression of E-cadherin closer to the control values. Keywords: gingival epithelium, chronic periodontitis, diode laser, Ki-67, p53, E-cadherin