LEUKOCYTE FUNCTION IN RATS WITH NATURALLY-OCCURRING GINGIVITIS

The severity of gingivitis in relation to abnormal macrophage chemotaxis and superoxide (O2-) production was investigated in rates with naturally occurring gingivitis (plaque-susceptible rats). Macrophage chemotaxis was measured by the membrane filter method; zymosan-activated serum was used as a chemo-attractant. O2- production was measured by the reduction of cytochrome c method. Opsonized zymosan, phorbol myristate acetate and calcium ionophore A231187 were used as stimulants. The macrophage chemotaxis and O2- production in the plaque-susceptible rats with deep pockets were significantly lower than those in the susceptible rats with shallow pockets or the normal group. In addition, there was a negative correlation between the severity of gingivitis in plaque-susceptible rats and macrophage chemotaxis or O2- production. These findings suggest that impairement of the host defence mechanisms due to the reduction in macrophage chemotaxis and O2- production is related to the progression of periodontal disease in plaque-susceptible rats.