Occludin在微波辐射致大鼠血脑屏障损伤中的变化及意义  

Changes and significance of occludin expression in rats with blood-brain barrier injury induced by microwave radiation

作　　者：李翔[1] 彭瑞云[1] 胡向军[1] 王水明[1] 高亚兵[1] 王丽峰[1] 董霁[1] 赵黎[1] 常公民[1] 王晓民[1] 苏镇涛[1] 

机构地区：[1]军事医学科学院放射与辐射医学研究所,北京100850

出　　处：《解放军医学杂志》2011年第7期765-769,共5页Medical Journal of Chinese People's Liberation Army

基　　金：国家科技重大专项(2008ZXJ09004-019);全军"十一五"科技攻关项目(08G145)

摘　　要：目的探讨长期低剂量微波辐射后大鼠海马组织中Occludin的表达及其在微波辐射致血脑屏障损伤中的作用。方法 156只二级雄性Wistar大鼠随机分为对照组及2.5、5、10mW/cm2辐射组(每组39只),分别采用0、2.5、5、10mW/cm2微波辐射,5次/周,6min/次,持续1个月。于辐射后6h及7、14、30、60、180d活杀大鼠(每组每个时间点5只),取海马组织,光镜和透射电镜观察海马血脑屏障结构改变;另取各组动物分别于6h及7、30d(每组每时间点3只)用2%伊文思蓝灌注后活杀大鼠,取海马组织,于激光共聚焦扫描显微镜下观察血脑屏障通透性变化;Western blotting、Real-time PCR和图像分析技术检测Occludin基因及蛋白表达的改变。结果 2.5、5、10mW/cm2微波辐射后7、14、30d,大鼠海马组织内血管周间隙增宽,内皮细胞间紧密连接结构模糊、增宽,星形胶质细胞肿胀。对照组海马组织中伊文思蓝局限于血管腔内,5、10mW/cm2组于辐射后6h均可见伊文思蓝弥散至血管外周,辐射后7d时更加显著,30d内未见恢复,且病变随辐射剂量增加呈加重趋势。5、10mW/cm2组大鼠海马中Occludin蛋白表达分别于第14天(P<0.05)和第7天(P<0.01)时开始降低,第30天时表达显著降低(P<0.01),而第60天时恢复至对照组水平(P>0.05)。2.5、5、10mW/cm2组海马中Occludin mRNA表达在辐射后6h和7d时无明显改变,14d时显著下降(P<0.01),30d时降至最低值(P<0.01),60d时恢复至对照组水平(P>0.05)。结论 2.5、5、10mW/cm2微波长期辐射可导致大鼠海马血脑屏障结构破坏,通透性增加,病变程度与辐射剂量有关;海马组织中Occludin表达减少可能参与了微波辐射致血脑屏障通透性升高的病理生理过程。Objective To observe the changes in occludin expression in hippocampus of rats injured by long-term microwave exposure at low dosage,and explore the mechanism of the effect of occludin on microwave-induced blood-brain barrier（BBB） injury.Methods A total of 156 male Wistar rats were assigned into 4 groups（39 each） according to the microwave dosage they received（0,2.5,5 and 10 mW/cm2）.Irradiation was given 5 times/week and 6 minutes for each exposure for one month.Five rats of each group were sacrificed at each time point（6h and day 7,14,30 and 60 after irradiation）,the structural changes in hippocampus tissues BBB were observed by light and electron microscopy.Another 3 rats of each group were sacrificed after an intravenous injection of 2% Evans blue（EB） at the time points of 6h and day 7 and 30 after irradiation,and the change in BBB permeability was examined by laser scanning confocal microscopy.Western blotting,real-time PCR and image analysis were used to detect the gene and protein expression of occludin in hippocampus of rats.Results After microwave irradiation in doses of 2.5,5 and 10 mW/cm2,respectively,on day 7,14 and 30,the astrocytes were found to be swollen,the capillary gaps of hippocampus were broadened and tight junction（TJ） structure was inconspicuous or widened.In sham-group（0 mW/cm2）,the red fluorescence of EB was limited in lumens of blood vessels,while in 5 and 10 mW/cm2 groups,Evans blue was dispersed surrounding the blood vessels at 6h and day 7 till day 30 in an irradiation dose-dependent manner.In 5 and 10 mW/cm2 groups,the expression of occludin protein in hippocampus decreased at day 14（P〈0.05） and day 7（P〈0.01）,and a remarkable decrease appeared at day 30 in both groups（P〈0.01）,followed by a recovery to the sham-group level at day 60（P〉0.05）.In the 2.5,5 and 10 mW/cm2 groups,mRNA expression of occludin began to significantly decrease at day 7 and 14 and it lowered to the nadir at day 30（P〈0.01）,followed by a recovery to the level

关 键 词：OCCLUDIN 微波 辐射损伤 血脑屏障 

分 类 号：R358.4[医药卫生—基础医学]