CD4＋CD25＋T细胞对小鼠破骨细胞形成及功能的影响

The effect of CD4＋CD25＋T cells on osteodasts in mice

目的明确CD4＋CD25＋T细胞对小鼠破骨细胞的形成及骨吸收功能的影响。方法应用免疫磁珠分选方法分离C57BL／6小鼠CD4＋CD25＋T细胞和CDllb＋单核细胞。在M-CSF及RANKL存在下，将分离的CDllb＋细胞培养3d，然后与CD3激活的CD4＋CD25＋T细胞或CD4＋CD25-T细胞再共同培养4d。CDllb＋细胞单独培养组为对照组。观察各组破骨细胞数目及骨吸收陷窝的数目。统计学方法采用单因素方差分析和U检验。结果所获得的CD4＋CD25＋T细胞，CD4＋CD25-T细胞及CDIlb＋细胞纯度均为90%以上。3组破骨细胞的形成数目分别为3．4±0．8、16．2±1．3、16．2±2．7（200x电子显微镜下5个视野的平均值）；骨吸收陷窝数目分别是15．3±2．8，47．4±4．8及50．3±5．0（100x电子显微镜下10个视野的平均值）。ANOVA及U检验的结果显示，CD4＋CD25＋T组的破骨细胞形成数目及骨吸收陷窝数目显著少于其他2组（P〈O．01）。结论CD4＋CD25＋T细胞对破骨细胞的形成及其骨吸收功能存在抑制作用，为阐明免疫异常所伴发的骨质疏松的机制提供了线索。

Objective To reveal the mechanism of inflanunation accompanied osteoporosis by examining the effect of CD4＋CD25 ＋ T cells on osteoclasts formation and bone absorption. Methods Mouse CDllb cells and CD4＋CD25＋ T cells were isolated using the microbead-based kits. The CDllb＋ monocytes were cultured alone or cocultured with CD4＋CD25＋ or CD4＋2D25- T cells, respectively. The numbers of osteoclasts and bone absorption pits were compared among the three groups. One-way ANOVA and U test was used for statistical analysis. Results The purities of isolated CD4＋CD25＋ T cells, CD4＋CD25- T cells and CD1lb＋ monocytes were all over 90% confirmed by flow cytometry. At day 7, the CD1lb＋ monocytes cocul- tured with CD4＋CD25 ＋ T cells generated significantly less osteoclasts, bone absorption pits than those cocultured with CD4＋CD25 T cells and those cultured alone （all P〈0.01）. The number of osteoclasts of the three groups was 3.4±0.8, 16.2±＋1.3, 16.2±2.7 （the mean number of osteoblasts of 5 high-power fields with 200 power electronic microscopy） respectively; the number of bone absorption pits was 15.3±2.8, 47.4±4.8 and 50.3±5.0 （the mean number of 10 field with 100 power electronic microscopy）respectively. The number of osteoclasts and bone absorption pits of the CD4＋CD25 ＋ T group were significantly lower than the other two groups （all P〈0.01）. Conclusion CD4＋CD25. T cells inhibit osteoclasts formation and its bone absorption effect, which highlights the role of CD4＋CD25＋ T cells on osteoporosis due to immune dysfunction.