两种脑出血动物模型的AQP4表达与磁共振成像的比较研究

Comparison of AQP4 expression and MRI images between two kinds of ICH animal models

目的比较两种脑出血(ICH)动物模型磁共振成像(MRI)的差异,并对其分子机制进行探讨。方法将胶原酶和自体血注入大鼠尾状核建立脑出血模型,分别于术后6h、12h、1d、2d、3d和7d进行磁共振成像扫描,观察两组脑出血模型血肿体积的大小;运用干湿重法、伊文思蓝(EB)测定法和免疫印迹分别检测两组脑出血模型的脑含水量(BWC)、血脑屏障(BBB)通透性和AQP4的表达变化。结果胶原酶模型组的血肿体积在脑出血后1d达到最大并持续至3d,自体血组的血肿体积在12h达到最大;胶原酶模型组的BWC在1d达到高峰并持续至3d,而自体血组BWC在2d逐渐降低;胶原酶模型组的EB含量在12h达到高峰并持续至2d,而自体血组EB含量在1d逐渐下降;两组模型的AQP4表达量在6h开始升高,1d达到高峰,2d逐渐降低。两组模型比较具有统计学差异(P<0.05)。结论胶原酶对BBB和细胞外基质的破坏以及AQP4的表达变化是两组脑出血模型血肿体积出现差异的重要原因。

Objective To compare the difference of AQP4 expression and MRI images between two kinds of ICH animal models. Mothods Collagenase and autoblood were injected into the caudate nucleus to establish ICH models in rats respectively. MRI was performed at 6h,12h, 1d, 2d, 3d and 7d for measuring the volume of hematoma. The changes of brain water content （BWC） were measured by wet and dry weight methods. Evan＇s blue（EB） was used to measure the integrity of BBB. The contents of AQP4 were detected by immunoblotting. Results For collagenase model, the hematoma volume and BWC reached peak at dl and maintained until d3,while EB contents reached the peak at 12h and maintained until d2. However, the hematoma volume of autoblood model animal reached the peak at 12h, and gradually reduced at d2. EB content gradually reduced at dl. The expression of AQP4 increased at 6h and reached the peak at dl and gradually reduced at d2 in two kinds of ICH models, which presented a significant differences in two ICH models （P〈0.05）. Conclusions The changes of AQP4 expression and the destruction of BBB or extracellular matrix induced by collagenase maybe the reasons of the difference in hematoma volume between two ICH models.