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目的 研究鼠大脑室管膜下区细胞 (SEC)放射性损伤的剂量效应关系及其相关基因表达规律。方法 采用 10MeV电子线照射昆明鼠全脑制作SEC放射损伤模型 ,以昆明鼠大脑SEC数、凋亡率和 p5 3,C jun ,C fos基因表达率为研究指标。结果 ①照射后 6h昆明鼠的SEC数开始下降 ,2 4,48h达最低值 ,12 0h有所恢复 ;照射剂量越高 ,SEC数越少 ;②照射后 6hSEC出现凋亡 ,2 4h凋亡率达到高峰 (5 ,10 ,2 0Gy组分别为 33.2 % ,33.3% ,37.0 % ) ,12 0h恢复 ;③照射后 2hSEC的C fos表达率达高峰 ,6h明显下降 ,2 4h恢复 ;④照射后 2hC jun表达率开始上升 ,6h达高峰 (5 ,10 ,2 0Gy照射组分别为 14.1% ,2 3.3%和 46 .5 % ) ,48h下降 ,12 0h恢复 ;⑤照射后 2hp5 3表达率明显上升 ,2 4h达到高峰 (5 ,10 ,2 0Gy组分别为 2 6 .5 % ,40 .8%和 6 6 .5 % ) ,48h下降 ,12 0h基本恢复。 结论 放射线诱导SEC的p5 3,C jun基因过表达和凋亡是放射性脑损伤的重要发病机制。
Objective To study the dose-effect relationship of radiosensitization of rat subventricular zone cells (SEC) and its related gene expression. Methods The whole brain of Kunming mice was irradiated with 10 MeV electron beam to make the SEC radiation injury model. The SEC number, apoptosis rate and the expression of C jun and C fos gene in Kunming mice were used as the research indexes. Results ① The SEC number of Kunming mice started to decrease at 6h after irradiation, reaching the lowest value at 4,48h and recovered at 120h. The higher the radiation dose, the lower the number of SECs. (2) The apoptosis rate of SEC at 6h after irradiation and the apoptosis rate at 24h Reached the peak (33.2%, 33.3%, 37.0% respectively in 5, 10 and 20 Gy groups) and resumed after 12 hours. (3) The expression of C fos in HepG2 reached the peak at 6h after irradiation, decreased significantly at 6h, restored at 24h. jun (P <0.05). The expression level of jun increased at 6h (14.1%, 23.3% and 46.5% respectively at 5,10 and 20 Gy groups), decreased at 48h and recovered at 12h. Peaked at 24 hours (26.5%, 40.8% and 6.6%, respectively) in 5,10 and 20 Gy groups, decreased in 48 hours, and recovered in 120 hours. Conclusions Radiation-induced overexpression of p5 3, C jun gene in SEC and apoptosis are important pathogenesis of radiation-induced brain injury.