重离子辐射对人外周血T淋巴细胞生物学性能的影响

目的研究重离子对人外周血T淋巴细胞增殖、凋亡等生物学性能的影响并探讨其机制,为肿瘤放射治疗的辐射防护提供实验依据和基础。方法 Ficoll分离法分离人外周血T淋巴细胞,采用12C重离子束坪区照射,照射样品能量为70 MeV、LET=29 keV/μm,照射剂量为1.0和2.0 Gy,剂量率为0.5 Gy/min。分别于照射后12、24h,RT-PCR检测凋亡相关基因Bcl-2,Bax,Caspase3,Caspase8和Caspase9的表达;于照射后24、48 h,CCK8法检测细胞增殖能力;于照射后24、48 h,采用AnnexinV-PE/7-AAD、AnnexinV-FITC/PI法检测凋亡发生,并采用RT-PCR检测凋亡相关蛋白Bcl-2、Bax和Caspase3的表达。结果重离子照射可明显抑制人外周血T淋巴细胞的增殖,随着剂量增大,抑制作用更加明显。同时,重离子照射可促进T淋巴细胞的凋亡,特别是对于晚期凋亡的诱导作用（P〈0.01）。RT-PCR检测结果显示,重离子辐射可抑制抗凋亡蛋白Bcl-2的表达,促进促凋亡蛋白Bax和Caspase3的表达（P〈0.01）。结论重离子辐射可显著影响抑制T淋巴细胞的增殖并促进其凋亡。

Biologic effect of heavy ion radiation on human peripheral blood derived T lympho-cytes

Objective To study the effect of heavy ion radiation on proliferation and apoptosis of human peripheral blood derived T lymphocytes and the mechanism .Methods T lymphocytes were isolated from heparinized whole blood samples by density gradient centrifugation using Ficoll before being irradiated with heavy ion beams 12 C.The accumulated absorbed dose （dose-rate values=0.5 Gy/min, and meanLET=29 keV/μm）.12 h and 24 h post-infection, total RNA of T lymphocytes was isolated , and the apoptosis related gene expression , including Bcl-2, Bax, Caspase3, Caspase8 and Caspase9, was detected by RT-RT-PCR.24 h and 48 h after irradiation, the proliferation was analyzed by CCK 8 kit.The cell apoptosis was detected by flow cytometry after being labeled with AnnexinV-PE/7-AAD or AnnexinV-FITC/PE.The expression of Bcl-2, Bax and Caspase3 was also assayed by RT-PCR.Results Data showed that heavy ion radiation could inhibit the proliferation of T lymphocytes obviously , and the inhibition ratio in cells that received 2 Gy dose was much high-er than in cells that received 1 Gy dose.Furthermore, heavy ion radiation promoted the apoptosis of T lymphocytes signifi-cantly.The results of RT-PCR showed that the mRNA expression of Bcl-2 was down-regulated in heavy ion radiation T lym-phocytes while the expression of Bax and Caspase 3 was up-regulated.Conclusion Heavy ion radiation can inhibit the pro-liferation and promote the apoptosis of human peripheral blood derived T lymphocytes .