中文摘要：

探讨了辐射诱导IEC-6细胞GSK3β信号转导途径的激活与细胞凋亡的关系，以及调控GSK3β信号转导途径对γ辐射诱导IEC-6细胞凋亡的保护作用。分别用RT-PCR检测GSK3β和caspase-3mRNA表达，Western-blot法检测GSK3β蛋白质磷酸化水平，放射活性法检测GSK-3β蛋白酶活性，caspase-3分光法检测caspase-3酶活性，Hoechst 33342荧光染色法检测细胞凋亡，琼脂糖凝胶电泳检测DNA片段化。发现6Gyγ射线照射可导致IEC-6细胞GSK3β基因表达上调，蛋白磷酸化水平降低，激酶活性增高；同时可使GSK3β介导的下游蛋白激酶caspase-3基因表达上调及酶活性增强；GSK3β和caspase-3特异性抑制剂预处理IEC-6细胞可使γ辐射诱导的IEC-6细胞凋亡细胞百分率降低，染色体DNA片段化消失。研究结果表明γ辐射可通过激活GSK3β从而进一步激活细胞凋亡相关蛋白激酶分子caspase-3，最终导致IEC-6细胞凋亡。抑制GSK3β和caspase-3激活可减轻6Gyγ辐射导致的IEC-6细胞凋亡，实验证实了GSK3β与caspase-3在γ辐射致肠上皮IEC-6细胞株损伤过程中的重要作用。

英文摘要：

The work is to determine the effects of γ-irradiation on GSK3 β coupled signaling transduction pathway in IEC-6 cells, and protect effects of regulation of GSK3 β and caspase-3 activation onyirradiation induced IEC-6 cells injuries. The changes of GSK-3 β and caspase-3 mRNA expression were determined by RT-PCR. The change of GSK-3 β phosphorylation was determined by western blotting. The changes of GSK-3 β enzymes activity were tested by radiation activity measurement. The changes of caspase-3 enzymes activity were assessed via a colorimetric assay with specific substrates. The IEC-6 cells apoptosis were determined by Hoechst 33342 staining and DNA ladder. The results show that 6Gy γ-irradiation increased apoptotic cell percentage in IEC-6 cells. Significant changes of GSK3 β and downstream signal transduction molecular caspase-3 in mRNA expression, GSK3 β protein dephosphorylation and protein enzymatic activation were observed after the irradiation. GSK3 β and coupled signal transduction pathway may play an important role to promote IEC-6 cells apoptosis. Inhibition of GSK3 β activation can provide protective effects against the irradiation induced IEC-6 cells apoptosis. Pretreatment with caspase-3 specific inhibitor has similar effects on IEC-6 cells, being characterized by decreasing apoptotic cell percentage and blockade of DNA fragmentation induced by the irradiation. GSK3 β and coupled signal transduction pathway plays a very important role in the irradiation induced IEC-6 cells injuries. Antagonism of GSK3 β and caspase-3 activation may be an important approach to protect intestinal epithelial function. These results are of clinical relevance in antagonism of the irradiation induced intestinal dysfunctions.