Localization of fibrinolytic activity during tooth eruption in rat

abstract — The fibrinolytic activity of erupting teeth and their surrounding tissues was studied in 14 young rats with a modification of the histochemical fibrin slide technique. Frozen tape-carried sections were coated with plasminogen-rich or plasminogen-poor fibrinogen, coagulated and incubated for 5 min to 1 h at 37°C. In the plasminogen-rich fibrin, zones of lysis were produced within a few minutes, indicating release of tissue activator of the fibrinolytic system. Distinct fibrinolysis was localized to periosteum as well as to predentin and odontoblasts. Zones of lysis were also observed in relation to some vessel walls, but those of the pulp and the periapical connective tissue did not show any fibrinolytic activity.