【摘要】 目的研究辐射诱导下Egr1基因启动子调控腺病毒介导的Smad7基因在C57BL小鼠肺内表达与放射剂量及放射后时相间的关系。方法将Egr1基因启动子的放射敏感元件和Smad7cDNA包装到复制缺陷型腺病毒内,制备成AD.EgrSmad7。小鼠气管内给AD.EgrSmad7,24h后单次全胸照射。324只小鼠随机分组进入实验,γ线8Gy照射后不同时间取肺组织测定Smad7蛋白含量,研究照射后Smad7基因肺内表达的时效关系。108只小鼠随机分组进入实验,以不同剂量照射后5h取肺组织测定Smad7蛋白含量,研究Smad7基因肺内表达与放射剂量的关系。采用Westernblot印迹法检测小鼠肺组织Smad7蛋白表达。结果γ线照射可明显诱导Egr1基因启动子调控腺病毒介导的Smad7基因在C57BL小鼠肺内表达,与对照组相比差异有统计学意义(P<0.01)。Smad7基因表达量与照射剂量和照射后间隔时间有关,单次照射0～12Gy间Smad7蛋白表达量随剂量升高而增加,15Gy时下降。照射后2～9hSmad7蛋白表达量最高(P<0.05),而后降低,15h降至接近正常水平。结论以腺病毒为载体,经射线诱导Egr1基因启动子能够调控Smad7基因体内表达,Smad7基因表达量与放射剂量及放射后间隔时间有关。更多还原

【Abstract】 Objective To investigate the time-effect relationship and dose-effect relationship of the expression of adenovirus mediating Smad 7 gene regulated by irradiation via Egr-1 promoter in the lung of C57BL mice. Methods Recombinant adenovirus (AD.Egr-Smad 7) was made up through replication-defective adenovirus enclosed radio-inducible elements from the Egr-1 gene promoter and cDNA encoding Smad 7. Mice infected by intratracheal instillation with AD.Egr-Smad 7 were irradiated to their whole lungs after 24 hours. 324 mice were randomly divided into 6 groups, and the lungs were harvested at different time points following irradiation with single dose of 8?Gy to observe the time-effect relationship of Smad7 gene expression with different time intervals. 108 mice randomly divided into 3 groups were irradiated respectively by different single irradiation dose and the lungs were harvested 5 hours after radiation to evaluated the dose-effect relationship of Smad 7 gene expression with different radiation doses. The expression of exogenous Smad 7 was detected by Western blot analysis. Results The expression of adenovirus mediating Smad 7 gene regulated by Egr-1 promoter could be induced by radiation markedly as compared with the control groups(P<0.01).The degree of Smad 7 gene expression was related to radiation dose and time interval after irradiation. The expression degree of Smad7 gene increased in a dose-dependent manner between 0-12?Gy, then decreased at 15?Gy. The expression degree of Smad 7 gene appeared to reach a peak 2-9 hours after start of radiation(P<0.05)and then coming down and almost returned to the normal 15 hours later. Conclusions The in vivo investigation demonstrates thatγ radiation markedly induces adenovirus mediating Smad 7 gene expression regulated by Egr-1 promoter. The expression of Smad 7 gene is correlated with radiation dose and time interval after irradiation.更多还原