大鼠创伤性脑损伤后Claudin-5表达水平变化的研究

Study on the expression changes of Claudin-5 after traumatic brain injury in rats

目的:探讨大鼠创伤性脑损伤后不同时间点血脑屏障通透性及Claudin-5表达水平的变化,为进一步研究创伤后脑水肿的机制及治疗时机提供理论依据。方法:大鼠随机分为对照组和脑损伤组,参照Feeney's的自由落体致伤法,制作大鼠顶叶局灶皮质挫裂伤模型。应用伊文兰(evansblue)法测定伤后不同时间点损伤灶皮层脑组织中EB含量;应用Westernblot法检测损伤灶脑微血管内皮细胞紧密连接相关蛋白Claudin-5的表达水平。结果:损伤灶皮层中EB含量在伤后1～6h明显增多,高峰期在3h。Westernblot结果显示损伤后1～6h,Claudin-5表达水平较对照组显著降低(P<0.05),3h最明显,24h与对照组差异无统计学意义。结论:大鼠顶叶局部脑挫裂伤可能通过下调紧密连接相关蛋白Claudin-5的表达水平,开放紧密连接,增加血脑屏障的通透性。

Objective： To evaluate the changes of blood-brain barrier （BBB） permeability and Claudin-5 expression level in rats after traumatic brain injury for different time, this study will help to further study the mechanism of brain edema and search optimal time for therapy. Methods： Rats were randomly divided into control group and brain-injury group. Brain injury animal modes were established according to Feeney＇s method. Evans Blue （EB） measurement in cortex was per- formed to determine the content of EB in damaged cortex at different time after injury, and the protein expression of Claudin-5 in microvessel endothelial cells was determined by Western blot. Results： The content of EB in damaged cortex was increased obviously at the time point of 1 to 6 h after injury. The extravasation peak course was at 3 h after injury. Western blot revealed that the expression of tight junction （TJ） associated with protein Claudin-5 was significantly decreased at the time point of 1 to 6 h after injury （P〈O.05）, and 3 h was prominent. Compared with control group, there was no sig- nificant difference in the 24 h. Conclusion： The increase the blood brain barrier （BBB） permeability caused by the parietal lobe local cerebral contusion of rats is possibly related to down-regulating the expression of TJ associated with protein Claudin-5.