Biologic effect of heavy ion radiation on human peripheral blood derived T lymphocytes

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 ¹²C. The accumulated absorbed dose (dose-rate values = 0.5 Gy/min, and meanLET = 29 keV/Vm). 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 CCK8 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 higher than in cells that received l Gy dose. Furthermore, heavy ion radiation promoted the apoptosis of T lymphocytes significantly. The results of RT-PCR showed that the mRNA expression of Bcl-2 was down-regulated in heavy ion radiation T lymphocytes while the expression of Bax and Caspase 3 was up-regulated. Conclusion: Heavy ion radiation can inhibit the proliferation and promote the apoptosis of human peripheral blood derived T lymphocytes. (authors)