Neutrophil and lymphocyte changes in blood and periodontal tissues under different immune states during periodontitis progression

Abstract

The importance of the immune system in the pathogenesis of periodontitis is being emphasized. To investigate the effects of different immune statuses on the progression of periodontitis, we induced periodontitis in neutrophil-deficient, lymphocyte- deficient, and dual neutrophil- and lymphocyte-deficient mice. The groups included BALB/c mice (Con-lym+/neu+), periodontitis- induced BALB/c and SCID mice (Peri-lym+/neu+ and Peri-lym–/neu+), and periodontitis-induced BALB/c and SCID mice treated with anti-Ly6G antibody (Peri-lym+/neu– and Peri-lym–/neu–). Periodontitis was induced by ligation of the mandibular first molar. Mice were sacrificed on days 0 (D0), 3 (D3), and 7 (D7) after ligation, and blood and periodontal tissue were analyzed. On D3, the AB area in the Peri-lym–/neu+ group was larger than in the Peri-lym+/neu+ group. The osteoclast on D3 was lower in the Peri-lym+/neu– group compared to the Peri-lym+/neu+ group. On D7, Ly6G+ cells were lower in both blood and periodontal tissue in the Peri-lym+/neu– group compared to the Peri-lym+/neu+ group, whereas CD3+ cell counts were higher only in periodontal tissue. In the Peri-lym–/neu– group, Ly6G+ cells were lower in both blood and periodontal tissue than in the Peri-lym–/ neu+ group, whereas CD3+ cells were higher in blood only. These results suggest that lymphocyte depletion delays AB loss and neutrophil depletion influences osteoclast formation at the early stage of periodontitis. In the late stage of periodontitis, lymphocyte depletion does not increase lymphocyte infiltration into periodontal tissue, even with neutrophil depletion. Collectively, different immune states may influence distinct stages of periodontitis progression.