目的·研究牙周炎对大鼠外周血中辅助性T（helper T，Th）细胞分群的影响，为牙周炎的免疫学研究提供依据。方法·采用分离牙龈、丝线结扎法建立大鼠牙周炎模型。分为牙周炎组（n=5），正常组（对照组，n=5），术后2周，进行牙周探诊。采用显微计算机断层扫描仪进行牙槽骨吸收高度测量，采用流式细胞术检测外周血Th1、Th2、Th17及调节性T（T-regulatory，Treg）细胞的比例。2组间的细胞比例差异采用独立样本t检验。结果·牙周炎组大鼠牙龈组织红肿、易出血，牙槽骨吸收明显，外周血中Th1（P=0.002）及Th17（P=0.028）细胞比例明显高于对照组，Treg细胞比例明显低于对照组（P=0.002），Th2细胞比例未有明显差异。结论·牙周炎促进大鼠外周血中促炎型Th细胞亚群的分化，抑制炎症调节型Th细胞亚群的分化。

Objective · To investigate the effects of periodontitis on the subsets of helper T (Th) cells in peripheral blood of rat models, so as to provide basis for the immunological study of periodontitis. Methods · Rat models of experimental periodontitis were induced by gingiva separation and silk tread ligation. They were divided into periodontitis group (n=5) and normal group (control group, n=5). Periodontal probing was performed two weeks after operation. Alveolar bone resorption was measured by micro-computed tomography (micro-CT). Peripheral blood was taken for flow cytometry to detect the proportions of Th1, Th2, Th17 and T-regulatory (Treg) cells. Difference of cell proportion between the two groups was performed with independent sample t-test. Results · The gingival tissue was swollen and easy to bleed, and alveolar bone resorption was obvious in the periodontitis group. Flow cytometry showed that the proportions of Th1 (P=0.002) and Th17 (P=0.028) cells in peripheral blood of the periodontitis group significantly increased, the proportion of Treg cells significantly decreased (P=0.002), and the proportion of Th2 cells did not change obviously. Conclusion · Periodontitis promotes the differentiation of pro-inflammatory Th cell subsets, while inhibiting the differentiation of inflammation-regulating Th cell subset in peripheral blood of rat models.