Impact of lipid peroxidation on collagen fibril degradation in experimental periodontitis

Lipid peroxidation analysis and identification of the main damage predictors lead to introduction of new diagnostic and treatment technologies into medical practice. The aim of the study was to evaluate the activity of free radical damage processes and identify their association with collagen metabolism disorders in the disease dynamics in experimental periodontitis. Materials and Methods. An experimental study was carried out on 60 white non-linear rats. A rat model of periodontitis was reproduced according to K.D. Shkolnaya and V.G. Atrushkevich method (Patent RU No. 2625295, December 07, 2017). The overall activity of free radical oxidation and antioxidant potential was assessed according to biochemiluminescence parameters. Lipid peroxidation activity was assessed according to the parameters of primary and secondary peroxidation products. Collagen metabolism was assessed by P.N. Sharaev method. Results. The rat model of periodontitis demonstrated a high level of free radical oxidation parameters. At the same time decrease in the antioxidant potential was observed throughout the experiment. It proved a significant inhibition of the antioxidant system ability to neutralize bioradical oxidation reactions. The resulting free radicals caused the collagen destruction, which formed the frame of the periodontal connective tissue structures. It was confirmed by hydroxyproline increase due to its free and peptide-bound fractions throughout the experiment. Finally, an increase in protein-bound hydroxyproline was determined against the background of high levels of free hydroxyproline, which was explained by the formation of pathological granulations and fibrillar collagen with an inferior short-chain structure. Conclusion. Chronic periodontitis is characterized by disturbances in the bioradical balance followed by the oxidative stress development, which induces the dystrophy of periodontal collagen structures. The data obtained substantiate the use of collagen peroxidation and metabolism markers as diagnostic criteria to predict the course of periodontitis, and also prove the importance of antioxidants.