Coagulation and fibrinolytic activity in rats with naturally occurring gingivitis.

It is well known that there are several coagulation factors and fibrinolysis factors, and these inhibitors are also present in blood and tissues. Normally, these factors balance each other. We measured antithrombin III (AT III), an important inhibitor of coagulation and alpha 2-plasmin inhibitor (alpha 2-PI), a factor inhibiting fibrinolysis in blood and gingival tissue of naturally occurring gingivitis rats (ODUS/Odu) and control rats (Res). Blood plasma and supernatants of gingival homogenate from ODUS/Odu and Res were used as samples. And concentrations of alpha 2-PI and AT III were measured by colorimetric assay using commercially available reagents. We found no difference in blood concentrations of alpha 2-PI or AT III between ODUS/Odu and Res groups. However, AT III in the gingiva showed a significantly higher value in the ODUS/Odu group versus that in the controls (p < 0.001). There was a high positive correlation between AT III in gingival tissue and pocket probing depth. Moreover, the fibrinolytic activity in saliva and the gingiva from ODUS/Odu increased with each passing month. Results suggest that both the decrease in blood coagulability and systemic enhancement of fibrinolytic activity due to increased AT III in gingival tissue are associated with the bleeding tendency and inflammatory response in the gingiva of ODUS/Odu.