The effect of vinblastine on the incorporation of [3H]-glycine into proteins of the periodontal ligament of impeded and unimpeded mouse incisors.

The effect of vinblastine on the protein metabolism of the periodontal ligament of impeded and unimpeded mouse incisors was studied by [3H]-glycine labelling and radioautography. The silver-grain concentration was determined in areas adjacent to the tooth, areas adjacent to bone and, as an internal control, in the dentine matrix. From 1 to 12 h there was no difference between treated and control animals; thus the drug did not alter protein biosynthesis. Later, the silver-grain concentration was significantly higher in areas adjacent to both bone and tooth in vinblastine-treated animals, suggesting a longer half-life of the labelled proteins. No significant differences between normal or unimpeded erupting incisors of both groups were detected. Dentine matrix showed a possibly higher re-utilization of the labelled amino acid in vinblastine-treated animals. The amount of labelled protein removed by collagenase was similar in both groups, while the concentration of grains due to collagenase-resistant proteins was significantly higher in treated animals, particularly at 96 h after the injection of labelled glycine. The relation between the increased amount of non-collagenous proteins in the periodontal ligament and the decrease in the rate of eruption caused by vinblastine was not established. However, among these proteins, fibronectin and proteoglycans are thought to be important factors in tooth eruption.