中文摘要：

目的探讨AIF、Bax和Bcl-2在中子及γ射线照射致肠道损伤中的表达变化及意义。方法290只BALB/c雄性小鼠,随机分为对照组（24只）、2.5Gy中子照射组（80只）、4.0Gy中子照射组（60只）、5.5Gyγ射线照射组（72只）及12.0Gyγ射线照射组（54只）,分别采用5.5和12.0Gyγ射线以及2.5和4.0Gy的中子照射,并于照射后6h,1、2、3、5、10d活杀,取空肠组织,用免疫组织化学和图像分析技术定量分析AIF、Bax及Bcl-2蛋白的表达变化。结果对照组小鼠空肠绒毛及隐窝上皮细胞质AIF呈强阳性,Bax和Bcl-2呈弱阳性。中子和γ射线照射后6h～1d,隐窝细胞核中AIF呈强阳性,表达明显增加（P〈0.01）;4.0Gy中子照射后Bax强阳性持续至照射后3d,表达明显增加（P〈0.01）。5.5、12.0Gyγ射线及2.5Gy中子照射后6h～5d,Bcl-2于上述部位呈强阳性,表达明显增加（P〈0.01）。4.0Gy中子照射后6h～3d,Bcl-2于上述部位呈弱阳性,表达无改变（P〉0.05）。结论中子及γ射线照射后空肠隐窝上皮细胞核中AIF表达增加,参与了肠上皮细胞凋亡的过程。中子照射时的Bax表达强于γ射线照射时,γ射线照射时的Bcl-2表达强于中子照射时,二者变化规律不同,提示中子和γ射线致肠道损伤具有不同的分子机制。

英文摘要：

Objective To explore the expressions of AIF,Bax and Bcl-2 in the intestine exposed to neutron and γ irradiation. Methods 290 male BALB/c mice,suffered to 5.5 and 12.0Gy γ ray or 2.5 and 4.0Gy neutron respectively,were sacrificed at 6h,1d,2d,3d,5d and 10d after irradiation. The small intestinal sections were used to observe the quantitative expressions of AIF,Bax and Bcl-2 by immunohistochemistry and image analysis. Results In control jejunum,AIF was strongly positive in the cytoplasm of the villi and cryptal epithelium. Bax and Bcl-2 were weakly positive in the above listed sites. AIF was strongly positive in the cryptal nucleus and the level is higher than that in control mice at 6 h~1 d after neutron and γ irradiation （P0.01）. Bax was strongly positive in the cytoplasm of the villi and cryptal epithelium at 6 h~1 d after neutron and γ irradiation （P0.01）; the expression level of Bax increased especially in 4.0 Gy neutron irradiated mice （P0.01）,in which the strong position could continued to 3 d after irradiation. The expression of Bcl-2 was strongly positive in the cytoplasm of the villi and cryptal epithelium at 6h~5d after 5.5,12.0 Gy γ ray and 2.5 Gy neutron irradiation,higher than that in the control mice （P0.01）. While Bcl-2 remained weakly positive in the above list sites after 4.0 Gy neutron irradiation and no significant difference was seen compared with the normal ones （P0.05）. Conclusions The cells in which AIF was strongly positive in the nucleus increased greatly after neutron and γ irradiation. This suggested that AIF was involved in the intestinal epithelial apoptosis induced by neutron and γ irradiation. The expression of Bax in neutron irradiated mice was higher that in γ irradiated mice; otherwise,the expression of Bcl-2 in neutron irradiated mice was lower in γ irradiated mice. Bax and Bcl-2 showed different change rules in neutron and γ irradiation caused intestinal injury which suggested neutron had different injury mechanism with γ ray.