微波辐射后大鼠脑内连接黏附分子-1表达与血脑屏障通透性的相关性研究

JAM-1 expression and the integrity of the blood-brain barrier after microwave radiation exposure

目的 探讨微波辐射后大鼠海马组织中连接黏附分子-1（JAM-1）表达及其与血脑屏障完整性的关系.方法 将160只雄性Wistar大鼠分为假辐射组及辐射组,辐射组又根据微波辐射功率密度不同细分为3个亚组,各辐射亚组分别接受10,30,100mW/cm2微波辐射,假辐射组微波辐射强度为0mW/cm2.各组大鼠分别于微波辐射后6h,1d,3d,7d及14d时活杀取脑,分别采用伊文思蓝染色、激光共聚焦显微镜、Western blot、RT-PCR及图像分析等手段检测大鼠血脑屏障通透性、脑皮质和海马中JAM-1表达的变化情况.结果 10、100mW/cm2微波辐射后3～14d期间,发现各辐射组大鼠海马组织中伊文思蓝含量均明显高于假辐射组,其中10,30mW/cm2辐射组伊文思蓝含量于微波辐射后7d内进行性增加（P〈0.01）,于微波辐射后14d时开始恢复;100mW/cm2辐射组伊文思蓝含量于微波辐射后14d期间进行性增加;假辐射组伊文思蓝局限于海马组织血管腔内,各辐射组伊文思蓝于微波辐射后3d时即弥散至血管腔外;10,30mW/cm2辐射组大鼠脑皮质及海马中JAM-1蛋白于微波辐射后7d内均显著降低（P〈0.05）,14d时开始恢复;100mW/cm2辐射组JAM-1蛋白在微波辐射后14d期间进行性下降（P〈0.01）;10,30及100mW/cm2微波辐射后6h时,发现大鼠海马中JAM-1mRNA表达均显著下降（P〈0.01）,其中10和30mW/cm2辐射组于微波辐射后7d时开始恢复,100mW/cm2辐射组则在微波辐射后7d期间进行性下降（P〈0.01）.结论 微波辐射可导致大鼠脑组织JAM-1表达减少,此改变与微波辐射剂量具有相关性,提示JAM-1有可能参与了微波辐射致血脑屏障通透性增高的病理过程.

Objective To investigate the expression of JAM-1 after microwave irradiation and its correlation with blood-brain barrier integrity. Methods A total of 160 male Wistar rats were divided into a sham radiation group and a radiation group. The radiation group was subdivided into three sub-groups treated with micrewaves at average power densities of 10, 30 and 100 mW/cm2. Rats in each group were sacrificed and their brain tissue sampled at 6 hours and 1, 3, 7 and 14 days after the irradiation. Evans blue （ EB ） dye, laser confocal microscopy,Western blotting, RT-PCR and image analysis were used to test the permeability of the blood-brain barrier and the expression of JAM-1 in protein and at the gene level in the rats＇ hippocampus and cortex. Results There was an increase of EB in the hippocampus 3 to 14 days after 10 and 100 mW/cm2 microwave irradiation. The EB level increased progressively in the 10 and 30 mW/cm2 groups within 7 d after irradiation but recovered by the 14th day. It also increased progressively in the 100 mW/cm2 group within 14 d after irradiation. In the hippocampus, EB was observed only in the lumens of the blood vessels in the sham group, but EB had diffused out of the blood vessels in the irradiated groups by the 3rd day after irradiation. After 10 or 30 mW/cm2 microwave irradiation, JAM-1 protein in the hippocampus and cortex decreased significantly within 7 d after irradiation but recovered by the 14th day. It decreased progressively in the 100 mW/cm2 group within 14 d after irradiation. The expression of JAM-1 mRNA in the hippocampus decreased significantly at 6 h after irradiation at all power levels, but it recovered within 7 days in the 10 and 30 mW/cm2 groups. Conclusions Microwave radiation can decrease the expression of JAM-1 in the hippocampus and cortex. The degree of decrease is positively correlated with the microwave radiation power. The change might involve increasing the permeability of the blood-brain barrier.