中文摘要：

目的 研究胚胎肝细胞对脑组织辐射损伤的修复作用.方法 24只雌性SD大鼠按随机数字表法分为对照组、模型组和治疗组,每组8只.后2组大鼠行一次性全脑照射20GyX线制备脑辐射损伤模型,造模后1、7、14、21 d治疗组大鼠后尾静脉注射雄性大鼠胚胎肝细胞1 mL（3×106个/mL）,模型组大鼠尾静脉注射等量生理盐水.于每次输注后12h取各组大鼠血清,分光光度计测定丙二醛（MDA）、超氧化物歧化酶（SOD）的水平,ELISA法测定肿瘤坏死因子α（TNFα）、白介素-1（IL-1）和白介素-6（IL-6）的含量.造模28 d后处死大鼠,RT-PCR检测治疗组大鼠脑组织Y染色体mRNA的表达,HE染色观察海马区脑组织的病理变化.结果 造模后1、7、14、21、28 d,与对照组比较,模型组和治疗组大鼠血清SOD水平较低,而MDA、TNFα、IL-1和IL6水平较高,差异有统计学意义（P＜0.05）;与模型组比较,治疗组大鼠血清SOD水平较高,而MDA、TNFα、IL-1和IL6水平较低,差异有统计学意义（P＜0.05）;RT-PCR结果显示治疗组大鼠脑组织有Y染色体mRNA表达;HE染色显示治疗组大鼠海马区虽可见凋亡状态的尼氏小体,但大脑皮质较模型组大鼠明显增厚,可见再生的海马神经元.结论 胚胎肝细胞能够修复脑组织的辐射损伤.

英文摘要：

Objective To study the cytothesis effects of haemopoietic stem cells （HSCs） from rat fetal liver on brain injury induced by radiation. Methods Twenty-four female SD rats were randomly divided into normal control group, model group and treatment group （n=8）. Total brain irradiation with 20 Gy X-ray was performed in the model group and the treatment group. Rats in the treatment group received infusion of HSCs from fetal liver （3×106 cells） 24 h, and 7, 14 and 21 d after irradiation, while rats in the model group and controls received infusion of saline at the same dosage. The serum of the rats was collected 12 h after infusion of HSCs each time; spectrophotometry was employed to detect the levels of malonaldehyde （MDA） and superoxide dismutase （SOD）; the contents of tumor necrosis factor α （TNFα）, interleukin （IL-1 and IL6） were measured by ELISA. Rats were sacrificed on the 28th d for assessing the pathological changes in brain tissue by HE staining and the mRNA level of Y chromosome by RT-PCR. Results Compared with that in the model group, the level of SOD in the treatment group was significantly higher, but the levels ofMDA, TNFα, IL-1 and IL6 were significantly lower in the treatment group 24 h, and 7, 14 and 21 d after the irradiation （P〈0.05）. The mRNA expression of Y chromosome was noted and apoptosis of Nissl bodies was also observed in the treatment group; the cerebral cortex in the treatment group was significantly thicker as compared with that in the model group （P〈0.05）; regenerative hippocampal neurons were observed in the treatment group. Conclusion HSCs from fetal liver can effectively repair the radiation brain injury.