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采用凝胶电泳移动变化分析(EMSA)方法,观察了 X射线全身照射后小鼠胸腺细胞及脾细胞内 NF-kB DNA结合活性的时程变化及其剂量效应关系。结果表明;胸腺细胞及脾细胞核蛋白提取物内存在两种与 kB位点特异结合的 NF-kB二聚体。 照射后两者的变化时程及剂量效应关系显然不同. 2Gy照射后胸腺细胞内 p50/p65的 DNA结合活住在 24~48h稍有升高,而 p50/p50的 DNA结合活性在照射后很快开始上升,于 4h达峰值,维持于高水平至 12h后逐渐下降。 照射后 12h电离辐射诱导 p50/p65复合物活性变化不明显,当剂量达 1Gy以上时p50/p50的DNA结合活性呈剂量依赖性升高。提示,中等以上剂量的电离辐射主要诱导具有转导抑制作用的复合物.对脾细胞核蛋白提取物剂量效应关系及2Gy照射后的时程研究表明,较低剂量辐射对 p50/p65 二聚体的表达有轻度刺激作用,较高剂量则显示抑制效应,而对 p50/p50二聚体的活住几乎无影响.提示,NF-kB在不同免疫器官内的构成及其对电离辐射的反应存在着差异。
The time-course changes of NF-κB DNA binding activity in mouse thymocytes and splenocytes after X-ray irradiation were observed by EMSA. The dose-response relationship was also observed. The results show that there are two NF-κB dimers that specifically bind to kB sites in the thymus and splenocyte nuclear protein extracts. After irradiation, the time course and dose-response relationship between the two obviously different. The DNA binding activity of p50 / p65 in thymocytes after 2Gy irradiation increased slightly from 24 to 48 hours, and the DNA binding activity of p50 / p50 began to increase rapidly after irradiation, reaching its peak at 4h and maintained at a high level until 12h After gradual decline. The change of p50 / p65 complex induced by ionizing radiation was insignificant at 12h after irradiation, and the DNA binding activity of p50 / p50 was increased in a dose-dependent manner when the dose was over 1Gy. It is suggested that ionizing radiation at medium dose and above mainly induces a complex with transduction inhibition. Dose-effect relationship of splenocyte nuclear protein extracts and time course after 2Gy irradiation showed that lower doses of radiation had a mild stimulating effect on the expression of p50 / p65 dimer, higher doses showed inhibitory effect, while p50 / Live p50 dimer almost no effect. Tip, NF-kB in different immune organs in the composition and response to ionizing radiation there are differences.