Objective The purpose of the present study was to observe the changes in CD4＋CD25＋Nrpl＋Treg cells after irradiation with different doses and explore the possible molecular mechanisms involved. Methods ICR mice and mouse lymphoma cell line （EL-4 cells） was used. The expressions of CD4, CD25, Nrpl, calcineurin and PKC-α were detected by flow cytometry. The expressions of TGF-131, IL-10, PKA and cAMP were estimated with ELISA. Results At 12 h after irradiation, the expression of Nrpl increased significantly in 4.0 Gy group, compared with sham-irradiation group （P〈0.05） in the spleen and thymus, respectively, when ICR mice received whole-body irradiation （WBI）. Meanwhile the synthesis of Interleukin 10 （IL-20） and transforming growth factor-β1 （TGF-β1） increased significantly after high dose irradiation （HDR） （〉 or = 1.0 Gy）. In addition, the expression of cAMP and PKA protein increased, while PKC-α, calcineurin decreased at 12h in thymus cells after 4.0 Gy X-irradiation. While TGF-β1 was clearly inhibited when the PLC-PIP2 signal pathway was stimulated or the cAMP-PKA signal pathway was blocked after 4.0 Gy X-irradiation, this did not limit the up-regulation of CD4＋CD25＋Nrpl＋Treg cells after ionizing radiation. Conclusion These results indicated that HDR might induce CD4＋CD25＋Nrpl＋Treg cells production and stimulate TGF-β1 secretion by regulating signal molecules in mice.
DONG Juan CongCHENG Guang HuiSHAN Yu XingWU NingSHAO Ming LongLI Peng WuJIN Shun Zi
