Positive effect of curcumin on experimental peridontitis via suppression of IL-1-beta and IL-6 expression level.

This study examined the effect of curcumin on T-helper (Th17) and T-regulatory (Treg) cells regarding the mRNA of cytokines/mediators in the gingiva. Thirty-five male albino Wistar rats were divided into four groups: Group 1: periodontitis (n = 9); Group 2: periodontitis with curcumin treatment (n = 8); Group 3: periodontally healthy with curcumin treatment (n = 10); and Group 4: periodontally healthy (n = 8). Curcumin was administered via oral gavage (30 mg/kg/day) for a total of 15 days. The gingival tissues were investigated regarding mRNA expressions of Th17/Treg cytokines with qRT-PCR. The distributional properties of the data were evaluated using the Anderson-Darling normality test. Kruskal-Wallis and Mann-Whitney U tests were employed for multiple group comparisons. Partial least squares regression discriminant analysis (PLS-DA) was used to evaluate the degree of contribution of each mRNA to the separation of treatment groups. When the periodontitis groups were compared, curcumin treatment resulted in lower IL-1ß (Group 2 median: 0.002, Group 1 median: 0.12) and IL-6 (Group 2 median: 0.031, Group 1 median: 0.078) and higher IL-17 (Group 2 median: 1.07, Group 1 median: 0.583) relative mRNA expression in Group 2 than in Group 1 (p < 0.001). Group 3 also had higher IL-10 relative expression (median: 0.067) than Groups 1 and 4 (median: 0.028, 0.007, respectively. p < 0.001). These results indicate that curcumin might be a promising agent for the prevention and/or treatment of periodontal diseases due to its decreasing effect on IL-1ß and IL-6 mRNA expression.

Effect of Curcumin on Systemic T Helper 17 Cell Response; Gingival Expressions of Interleukin-17 and Retinoic Acid Receptor-Related Orphan Receptor γt; and Alveolar Bone Loss in Experimental Periodontitis.

BACKGROUND: Curcumin has anti-inflammatory and antioxidant effects and is reported to have many biologic activities. The current study examines effect of curcumin on: 1) systemic T helper 17 (Th17) cell response; 2) gingival expressions of interleukin (IL)-17 and retinoic acid receptor-related orphan receptor (ROR) γt; and 3) alveolar bone loss (ABL) in experimental periodontitis. METHODS: Thirty-eight male albino Wistar rats were divided into four groups: 1) group 1 = periodontitis; 2) group 2 = periodontitis with curcumin treatment; 3) group 3 = periodontally healthy with curcumin treatment; and 4) group 4 = periodontally healthy. Curcumin was administered via oral gavage (30 mg/kg/d) for 15 days. After sacrifice via exsanguination, the following serum levels were determined using enzyme-linked immunosorbent assay: 1) IL-1ß; 2) IL-6; 3) IL-17A; 4) IL-23; and 5) transforming growth factor- ß. Morphometric evaluation of ABL was conducted and expression levels of IL-17 and RORγt in gingival tissues were evaluated immunohistochemically. RESULTS: Group 2 had significantly lower ABL than group 1 (P <0.0125). Highest expression levels of IL-17 and RORγt were observed in group 1 and were significantly higher than those in all other groups (P <0.0125). The only serum biochemical parameter significantly different among groups was level of IL-23 (P <0.05). Serum IL-23 levels were higher in groups 1 and 2 than groups 3 and 4 (P <0.0125); however, they were not significantly different for groups 1 and 2 (P >0.0125). CONCLUSION: Curcumin seems to be a promising host modulatory agent in periodontal disease pathogenesis regarding IL-17/IL-23 axis, with a decreasing effect on ABL and gingival expressions of IL-17 and RORγt.