[Biochemical properties of aging of rat periodontium].

The content of proteins and nucleic acids and activity of acid and alkaline proteases, RNases, phosphatases and alpha-amylase were studied in the gum and alveolar bone or rats at the age of 1, 3, 6, 12, 18 and 24 months. It is found that a degree of periodontal atrophy strongly and directly correlates with the age of rats. The concentration of DNA and RNA in alveolar bone and of RNA in gum decreases with the age. The hydroxyproline content of periodontal tissues continuously increases till the age of 18th month and then considerably decreases. The activity of trypsin-like proteases, cathepsins and alkaline RNase in periodontal tissues increases reaching the maximum at the age of 6-18 months, and the activity of alkaline phosphatase decreases in the process of aging.