Epithelial migration in organ culture: Role of protein synthesis as determined by metabolic inhibitors

Abstract

The role of protein synthesis in epithelial migration in the first 24 h after injury was assessed by exposing explants of rat palatal mucosa to the inhibitors puromycin, cycloheximide and 5-bromodeoxyuridine (BUdR). Epithelial migration was determined by morphological examination of fixed and sectioned explants and the extent of migration was estimated by counting the number of nuclei that had moved beyond the line of incision. The effects of these inhibitors on epithelial migration and on the relevant biochemical pathways were correlated by the use of dual label radioactive tracer technique. With puromycin and cycloheximide it was found that a significant depression of protein synthesis (greater than 50% of the control) was required before epithelial migration was completely inhibited. BUdR had no significant effect on the extent of epithelial migration or on protein synthesis at any concentration tested but significantly depressed thymidine incorporation at the higher concentrations of inhibitor (7.5 and 75 μg/ml). The results of these experiments are interpreted as indicating that ‘new’ protein synthesis is not required for the initiation of epithelial migration following injury and alternative mechanisms are discussed.