Morphological and immunological changes in tissues during experimental parodontitis in rats

   The purpose of the study: to evaluate the morphological and immunohistochemical parameters of the rat periodontium in the model of experimental periodontitis.

   Materials and methods. Experimental periodontitis was formed in male Wistar rats aged 18–20 weeks and weighing 200–300 g. Periodontitis was modeled by detaching the gums with the end of a spear-shaped scalpel (No. 11) in combination with injections of 10 % ethanol solution with 0.25 % novocaine solution in within 7 days. The inflammatory process was assessed morphologically and histologically. In blood serum and homogenate of periodontal tissues, the level of cytokines was determined using a multiplex analysis system (USA). Histological sections were made at the level of the incisors of both jaws, stained with hematoxylin-eosin and immunohistochemically with rabbit monoclonal antibodies (SP7). Statistical data processing was carried out using one-way Kruskal-Walliss analysis of variance. Significance of differences between groups (p) was assessed using pairwise comparisons of Dwass-Steele-Critchlow-Fligner.

   Research results. On the seventh day of the experiment, the gum acquired a cyanotic hue, its significant edema was observed. Histologically, the presence of a periodontal pocket, infiltration of tissues with leukocytes, macrophages, fibroblasts, thickening of the gingival epithelium, destruction of the periodontium and resorption of the bone beams of the alveoli were recorded. There was an increase in the concentrations of cytokines in rats, to a greater extent in the blood serum. The most pronounced increase was in TNFα and IFN γ, the minimum increase was observed in IL 6. It was found that the number of macrophages and B-lymphocytes increased equally by 8.5 times (p = 0.000001), the number of T-lymphocytes increased by 5.5 times (p = 0.000001).

   Conclusion. In the model of chronic periodontitis, we have shown that there is activation of all parts of the immune system, with a predominance of the humoral part of the immune system, manifested by an increase in the levels of cytokines both in blood serum and tissues and an increase in the number of immunocompetent cells in periodontal tissues.

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