[Inhibition of CD4(+)T cell infiltration by interleukin-10 competent B cells in periodontitis tissues]

Objective: To study the immune regulation function of high expressing interleukin-10 (IL-10) in B cells on CD4(+)T-cells in periodontitis mouse model. Methods: Twenty-four 7-weeks-old female C57BL/6 mice were randomly and equally assigned into 4 groups: the healthy control group (HC group, n=6), the ligation combined Porphyromonasgingivalis (Pg) infection group (P group, n=6), the ligation combined Pg infection with non-stimulated B cell transfer group (P+NSB group, n=6) and the ligation combined Pg infection with stimulated B cell transfer group (P+SB group, n=6). Ligation combined Pg infection of the maxillary second molar was used to induce periodontitis of mice. The exogenous non-stimulated B cells or stimulated B cells were injected into the palate gingivalat the 5th day after ligation, and all mice were sacrificed at the 14th day. HE stain was used to detect the histological of periodontal tissues, toluidine blue stain was used to analysis the alveolar bone loss, immunofluorescence stain was used to detect the expression of CD4(+)T-cell and IL-10, immunohistochemical was used to detect the expression of receptor activator of NF-κB ligand (RANKL) and IL-1β. Results: Results of HE staining showed that more hyperplasia of gingival epithelium and the alveolar bone resorption in P group, P+NSB group and P+SB group compared with HC group. Results of toluidine blue staining showed that the alveolar bone losses in P group [(0.668±0.041) mm(2)], P+NSB group [(0.750±0.039) mm(2)] and P+SB group [(0.517±0.038) mm(2)] were significantly increased compared with that in HC group [(0.336±0.029) mm(2)](F=146.051, P<0.01), and the alveolar bone resorption was significantly increased in P+NSB group compared with that in P group (F=146.051, P<0.01). However, compared with P+NSB group and P group, the alveolar bone loss in P+SB groupwas significantly decreased (F=146.051, P<0.01). Results of immunofluorescence staining showed that CD4(+)T-cells expressed in P group [(287.5±37.9) cell/mm(2)], P+NSB group [(314.6±53.3) cell/mm(2)] and P+SB group [(185.4±42.9) cell/mm(2)] were higher than that in HC group [(12.5±13.7) cell/mm(2))(F=71.284, P<0.01). Compared with P group and P+NSB group, CD4(+)T-cells expression in group P+SB was decreased (F=71.284, P<0.01). IL-10 levels were increased in P group [(111.7±20.4) cell/mm(2)], P+NSB group [(126.7±15.1) cell/mm(2)] and P+SB group [(191.0±22.6) cell/mm(2)] compared with that in HC group [(22.7±4.3) cell/mm(2)] (F=98.516, P<0.01), and the IL-10 expressed in P+SB group was significantly higher than those in P+NSB group and P group. Results of immunohistochemical tests showed that RANKL expressions in gingival tissues among P group [(674.0±71.5) cell/mm(2)], P+NSB group [(831.0±97.5) cell/mm(2)] and P+SB group [(420.1±40.8) cell/mm(2)] were significantly higher than that in HC group [(69.3±29.1) cell/mm(2)] (F=154.886, P<0.01). However, it dramatically decreased in P+SB group compared with those in P group and P+NSB group.The IL-1βexpression in P group [(447.8±40.8) cell/mm(2)], P+NSB group [(512.5±38.2) cell/mm(2)] and P+SB group [(281.6±32.4) cell/mm(2)] were significantly higher than that in HC group [(50.8±20.9) cell/mm(2)], and it also higher in P+NSB group compared with in P group. However, it decreased in P+SB group compared with those in P group and P+NSB group (F=221.185, P<0.01). Conclusions: High expression IL-10 in B cell smight inhibit alveolar bone loss, RANKL and IL-1β expressions and CD4(+)T-cell infiltration through IL-10.