Cytokine gene expression profiles during initiation, progression and resolution of periodontitis

Aim Variations in the expression of cytokines during the progression of periodontitis remain ill‐defined. We evaluated the expression of 19 cytokine genes related to T‐cell phenotype/function during initiation, progression and resolution of periodontitis, and related these to the expression of soft and bone tissue destruction genes ( TDG s). Materials and Methods A ligature‐induced periodontitis model was used in rhesus monkeys ( M. mulatta ) ( n  = 18). Gingival tissues were taken at baseline pre‐ligation, 2 weeks and 1 month (Initiation) and 3 months (progression) post ligation. Ligatures were removed and samples taken 2 months later (resolution). Total RNA was isolated and the Rhesus Gene 1.0 ST (Affymetrix) used for gene expression analysis. Significant expression changes were validated by q RT ‐PCR. Results Disease initiation/progression was characterized by overexpression of Th17/Treg cytokine genes ( IL ‐1 β , IL ‐6, TGF β and IL ‐21) and down‐regulation of Th1/Th2 cytokine genes ( IL ‐18 and IL ‐25). Increased IL ‐2 and decreased IL ‐10 levels were seen during disease resolution. Several Th17/Treg cytokine genes positively correlated with TDG s, whereas most Th1/Th2 genes exhibited a negative correlation. Conclusion Initiation, progression and resolution of periodontitis involve over‐ and underexpression of cytokine genes related to various T‐helper subsets. In addition, variations in individual T‐helper response subset/genes during disease progression correlated with protective/destructive outcomes.