中文摘要：

目的观察辐射对淋巴瘤EL-4细胞P21蛋白表达及基因转录的影响。方法应用RT—PCR方法检测经辐射诱导的淋巴瘤EL-4细胞中p21基因转录的时程和量效变化，采用流式细胞术检测P21蛋白表达的时程和量效变化。结果4．0GyX射线照射后p21基因转录水平立即增高，至照射后4h达峰值，持续至照射后24h。4．0GyX射线照射后8hEL-4细胞p21蛋白表达开始增高，24h达峰值，持续至照后72h（P〈0．01）。0．5～6．0GyX射线照射后4h，EL-4细胞p21基因转录水平均高于对照组，其中以4．0GyX射线照射后基因转录水平最高，1．0～6．0GyX射线照射后，EL-4细胞p21蛋白表达均明显增高（P〈0．05）。结论辐射可诱导淋巴瘤EL．4细胞P21蛋白表达及基因转录，并呈时间和剂量依赖关系。

英文摘要：

Objective To explore the effects of ionizing radiation on p21 protein expression and gene transcription in EL-4 mouse lymphoma cells. Methods RT-PCR was used to detect p21 gene transcription in duration and dose changes in EL-4 cells among radiation-induced lymphoma mice, and flow cytometry was used to detect time course and dose changes of p21 protein expression. Results Time course results showed that p21 transcriptional level immediately incre- ased after 4.0 Gy X-ray radiation, and it reached the peak after four-hour radiation, lasting for 24-hour radiation. Expression of p21 began to increase eight hours after 4.0 Gy X-ray radiation, and it peaked after 24-hour radiation, lasting for 72-hour radiation （19 〈 0.01 ）. The results also showed that p21 gene transcription level of EL -4 cell was higher than that of the control group four hours after 0.5 - 6.0 Gy irradiation, of which, the level of 4.0 Gy was the highest. P21 protein expression of EL-4 increased significantly after four hours 1.0 - 6.0 Gy X-ray irradiation （P 〈 0.05）. Conclusions The p21 gene transcription and protein expression can be increased by X-radiation in time- and dose-dependent manners in EL-4 cells.