电磁脉冲致大鼠血脑屏障通透性增加过程中actin的作用

The role of actin in the electromagnetic pulse induced blood-brain barrier opening

目的探讨脑微血管内皮细胞肌动蛋白actin在电磁脉冲(EMP)诱导的血脑屏障通透性增加中的作用。方法 36只健康成年雄性SD大鼠按体重随机分为假辐照组和辐照组,EMP辐照参数为:场强200kV/m,脉宽7ns,脉冲次数200,脉冲重复频率1Hz。辐照后不同时间取材,尾静脉注射伊文思蓝及白蛋白免疫印迹法观察EMP辐照后血脑屏障通透性的变化;免疫印迹法检测脑组织和脑微血管中actin的表达情况;免疫荧光法观察脑微血管内皮细胞actin分布情况。结果白蛋白免疫印迹和伊文思蓝荧光结果显示EMP辐照后由血液进入脑组织中的白蛋白3h时最多,与假辐照组相比差异具有统计学意义(P<0.05),至辐照后12h恢复至正常水平;EMP辐照后脑组织和脑微血管中actin蛋白表达量与假辐照组相比无统计学差异(P>0.05);免疫荧光结果显示其在脑微血管内皮细胞上的分布也无明显改变。结论 actin在EMP辐照致血脑屏障开放过程中不发挥主要作用。

Objective To study the effect of electromagnetic pulse on the expression and distribution of actin in rat brain microvessels. Methods 36 Male SD rats were sham or whole-body exposed to EMP at 200 kV/m for 200 pulses （1 Hz）, and the pulse width was 7ns. At 0.5, 1, 3, 6, 12 h after EMP exposure, the permeability of the BBB was estimated by using Evens Blue and albumin as tracers, the expression of actin in rat cortex and microvessels of frontal lobe was determined by western blotting and the distribution of actin was examined by immunofluorescence. Results The protein level of albumin increased at 1h, 3h and 6h after EMP exposure, and the peak was at 3 h （P〈0.05）. However, the protein level of actin in both cortex and microvessels of rat brain frontal lobe did not change significantly （P〉0.05）, moreover, the distribution of actin in microvascular endothelial cells had no obvious alternation. Conclusions Our data suggested that actin was not involved in EMP-induced BBB opening.