Relationship Between Interleukin-1β And IL-1 Receptor Antagonist Levels In Gingival Crevicular Fluid And Chronic Periodontitis

Aim: Interleukin-1β (IL-1β), a multifunctional proinflammatory cytokine, has been involved in the pathogenesis of periodontal destruction. IL-1 receptor antagonist(IL-1ra), another member of IL-1 family, binds to the IL-1 receptor but fails to activate cells, thus inhibiting the biologic activities of IL-1 β . The aim of this study are to investigate: (1)IL-1β and IL-1ra concentrations in gingival crevicular fluid(GCF) of periodontally healthy and chronic periodontitis sites; (2)the relationship between GCF IL-1β and IL-lra levels. Method: 15 GCF samples were harvested from non-inflamed sites of 10 periodontally healthy subjects, 15 GCF samples from non-inflamed sites and 43 GCF samples from chronic periodontitis sites (including 28 GCF samples from BOP positive sites and 15 GCF samples from BOP negative sites) of 33 patients with chronic periodontitis. Clinical measurements(GI, PPD and CAL) were recorded for each tooth after obtaining a GCF sample. The concentrations of IL-1β and IL-lra in GCF were quantified by sensitive enzyme linked immunosorbent assay(ELISA). Results: (1) The mean concentrations of IL-1 β and IL-lra and the average value of 10000IL-1β/IL-lra for non-inflamed sites were 61.891 ±20.719pg/ml, 739.410±249.121ng/ml and 0.857±0.375, respectively. They were all of no difference for the non-inflamed sites betweenthe periodontally healthy subjects and the patients with chronic periodontitis(P >0.05). (2) The mean concentration of IL-1β (224.402±87.416pg/ml)and the average value of 10000IL-lβ /IL-1ra(6.813±0.375) for periodontitis sites were much greater than that for healthy sites (P< 0.0001) and in contrast the mean concentration of IL-lra for periodontitis sites(366.722 ± 104.188ng/ml) was lower than that for healthy sites (P< 0.0001). For all sites, a strong inverse relationship was found between IL-1β and IL-lra levels in GCF (r=-0.730, P <0.01) . (3) The mean concentration of IL-1β and the average value of 10000IL-1β /IL-lra for BOP positive periodontitis sites were greater than that for BOP negative sites(P< 0.0001) and the mean concentration of IL-lra was in contrast (P<0.01). (4)Both of IL-1β and 10000IL-1β /IL-1ra value had the positive correlations with GI, PPD and CAL(P<0.01). And the negative correlation was found between GI and IL-1ra(P<0.05, P<0.01). Conclusions: The increasing production of IL-1β and decreasing production of IL-lra result in the increase of the 10000IL-1β /IL-1ra value and the corresponding enhancement of IL-1β activity which may play an important role in the initiation of periodontitis and in the intensified inflammatory response of active stage of periodontitis. Furthermore, the GCF level of IL-1β and the value of 10000IL-1β /IL-1ra, especially the latter one, are closely associated with the severity of chronic periodontitis and may also be valuable indicators of the clinical activity of periodontitis.