Oxidative modification of proteins in the process of experimental periodontitis development.

The article reveals patterns of changes in the parameters of oxidative modification of proteins for different periods of the inflammatory process in periodontal tissues during periodontitis. Biochemical researches of phenylhydrazones, aldehyde-, and ketone derivatives of neutral and basic proteins were determined in the blood of white rats on the 7th, 14th, and 30th days of the experimental periodontitis development, as well as in intact animals. The method for determination of the oxidative modification of proteins was based on the interaction of oxidized amino acid residues with 2,4-dinitrophenylhydrazine to form 2,4-dinitrophenylhydrazones. At the early stage of experimental periodontitis development, i.e., on the 7th day, an increase in the products of oxidative modification of proteins of basic and neutral nature was observed in the blood serum, but later, on the 14th day, this index changed in opposite direction, i.e., it began to decrease; however, it was higher relative to the intact group of animals. The obtained factual data evidence that under the conditions of experimental periodontitis formation, there is an intensive increase in the level of oxidative modification of proteins especially in the early period of the inflammatory process development.