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目的 观察脐血T淋巴细胞及其亚群低剂量辐射 (LDR)效应。方法 对脐血T淋巴细胞及其亚群分离、培养 ,LDR后用3 H 胸腺嘧啶核苷 (3 H TdR)掺入法观察其DNA合成和抗肿瘤细胞K562 活性 ,集落培养观察脐血干细胞造血能力。结果 脐血T淋巴细胞及其亚群CD4、CD8、CD19细胞经 2、5、10、2 0cGy的LDR与 0cGy(对照组 )比较 ,3 H TdR掺入明显增加 ,5cGy的LDR与 0cGy比较 ,3 H TdR掺入分别为 14 3 2 %、14 6 8%、14 5 4 %、15 7 9%。对K562 细胞杀伤作用经 2、5、10、2 0cGy的LDR均有明显增高 ,5cGy的LDR与 0cGy比较杀伤率和NK相对活性分别为 38 3%和 172 0 %。造血干细胞集落数无差别 ,5cGy的LDR与 0cGy比较分别为 12 2和 12 1个。结论 适宜的LDR对脐血T淋巴细胞和亚群的DNA合成有刺激作用 ,能增加体外抗肿瘤细胞K562活性 ,并保持脐血干细胞造血能力
Objective To observe the effects of low dose radiation (LDR) on cord blood T lymphocytes and its subpopulations. Methods The DNA synthesis and anti-tumor activity of K562 cells were observed by 3H-dT incorporation after culture and LDR of cord blood T lymphocytes and their subpopulations. Colony culture was used to observe the proliferation of cord blood stem cells ability. Results Compared with 0cGy (control group), LDH of umbilical cord blood T lymphocytes and its subsets of CD4, CD8 and CD19 cells were significantly increased by 2, 5, 10 and 20 cGy LDRs and 0cGy, The incorporation of 3 H TdR was 14 3 2%, 14 6 8%, 14 5 4%, 15 7 9%, respectively. The cytotoxicity of K562 cells to 2, 5, 10 and 20 cGy was significantly higher than that of 5 and 5 cGy, respectively. The killing rate and NK relative activity of LDR of 5 cGy and 0 cGy were 38 3% and 172 0% respectively. There was no difference in the number of hematopoietic stem cell colonies. The LDR of 5cGy was 12 2 and 12 1, respectively, compared with that of 0cGy. Conclusion Suitable LDR can stimulate the DNA synthesis of T lymphocytes and subpopulations in cord blood, increase the anti-tumor activity of K562 in vitro and maintain the hematopoietic capacity of cord blood stem cells