中子及γ线照射小鼠肠组织中TNF-α的表达及其意义

摘要

目的 研究经中子及γ线照射后小鼠肠组织中TNF-α的表达情况及其意义.方法 350只二级雄性BALB/c小鼠,经不同剂量的中子和γ线照射,于照后6、12h及1、2、3、4、5、7、10、14、21、28天分批活杀,采用免疫组化染色等技术观察TNF-α在肠组织中的表达情况.结果 在正常肠黏膜中,TNF-α主要见于肠绒毛间质、黏膜下及淋巴组织中的巨噬细胞浆内; 2.5Gy中子照后2天内,上述阳性部位TNF-α的表达进行性减少;3～7天其在巨噬细胞及隐窝细胞胞质内的表达明显增加,5天达高峰,14天恢复至正常水平.4.0Gy、5.5Gy中子及12Gyγ线照射后4天内,TNF-α的表达进行性减少;5.5Gy γ线照后6～12h,TNF-α的表达增多,照后1天减少,2～5天增加,3天达高峰,10天恢复至正常水平.TNF-α的表达在肠黏膜损伤时减少,于损伤后恢复的早期增多.结论 中子和γ线照后肠内源性TNF-α表达具有不同的变化规律,并参与了肠放射损伤及修复的病理生理过程.%Objective To study the expression of tumor necrosis factor alpha (TNF-α) in the intestine of mice irradiated by neutron and γ rays.Methods 350 male BALB/c mice were irradiated with neutron and γ rays of different doses, and sacrificed at 6 and 12hours, 1, 2, 3, 4, 5, 7, 10, 14, 21 and 28 days after irradiation.The TNF-α in the mice intestinal tissue was detected by means of immunohistochemistry and image analysis.Results In normal control mice, TNF-α was expressed in the cytoplasm of macrophages in intestinal villus interstitium, submucosa and lymph tissue.After 2.5Gy neutron radiation, TNF-α was decreased progressively within 2 days, increased obviously in macrophages and crypt cells during 3rd～7th day, reached the peak at 5th day and recovered to normal level at 14th day and TNF-α was decreased progressively within 4 days after 4.0 and 5.5Gy neutron and 12Gy ray irradiation.TNF-α was increased obviously in 6～12 hours, decreased at 1st day, increased at 2nd～5th day, peaked at 3rd day and recovered at 10th day after 5.5Gy ray irradiation.Conclusion Neutron and ray radiation induce different expression profile of endogenous TNF-α in small intestine, which may be related with the pathologic courses of irradiation-induced damage and repair of intestine.