HISTOLOGICAL EVALUATION OF STRUCTURAL CHANGES IN THE GINGIVA IN EXPERIMENTAL PERIODONTITIS AND FOLLOWING CORRECTION WITH MESENCHYMAL STEM CELLS

Abstract

Periodontitis is a chronic inflammatory disease characterized by disruption of the gingival epithelial barrier, disorganization of the connective tissue matrix, microcirculatory impairment, and progressive destruction of the tooth-supporting tissues. Although conventional treatment methods effectively control microbial biofilm and inflammation, complete structural restoration of the periodontal complex remains a major clinical challenge. Mesenchymal stem cells are increasingly regarded as promising tools in regenerative dentistry due to their paracrine, immunomodulatory, proangiogenic, and matrix-regulating effects. Objective - to evaluate morphological changes in the gingiva in lipopolysaccharide-induced experimental periodontitis and after correction with umbilical cord-derived mesenchymal stem cells. Materials and methods. Periodontitis was modeled in rats by intragingival administration of lipopolysaccharide into the interdental papilla between the first and second molars. Correction was performed using human umbilical cord-derived mesenchymal stem cells, administered once intragingivally into the gingival tissues at the site of the modeled pathological process. The morphological examination was performed on day 20 of the experiment. Gingival tissues were examined by light microscopy of semithin sections stained with methylene blue. Results. Lipopolysaccharide-induced periodontitis was characterized by epithelial disorganization, increased keratinization, intercellular edema, dystrophic changes in epithelial cells, leukocytic infiltration, edema of the lamina propria of the mucosa, disorganization of collagen fibers, and microcirculatory disturbances. After local administration of mesenchymal stem cells, gingival tissues showed less pronounced edema and cellular infiltration, a more orderly structure of the epithelial layer, better preservation of collagen fibers, and less pronounced microcirculatory disturbances. Conclusions. The obtained results indicate the presence of morphological signs of a corrective effect of umbilical cord-derived mesenchymal stem cells in experimental periodontitis. Obtained data substantiate the need for further morphometric and immunohistochemical studies of the effects of mesenchymal stem cells in periodontal tissues.