Abstract
Effect of age on collagen synthesis, protein synthesis and the activities of prolyl hydroxylase, collagenase and cathepsin D in the rat gingiva was studied. Male wistar rats of 4, 11-12 and 56-64 weeks old were used as young, adult and old groups, respectively. The results are as follows:
1) collagn synthesis of gingiva markedly decreased with aging; the value was about one-third in adult group and about one-tenth in old group as compared with that of young group. Protein synthesis also decreased but the rate of the decrease was slight when compared with the rate of collagen synthesis.
2) A marked decrease in prolyl hydroxylase activity was also found; the activity changed almost parallel with the rate of collagen synthesis.
3) collagenase activity was about a half in adult group and one-fourth in old group as compared with the activity of young group. A significant decrease in cathepsin D activity was also found.
These results indicate that the turnover of collagen in the rat gingiva markedly decreases with aging.
