大鼠脑局部星形细胞肿胀的CT灌注成像及病理学研究

Study of local swelling of cerebral astrocytes with CT perfusion and histopathological technique in rats

目的研究脑局部星形细胞肿胀对局部脑血流的影响。方法选取体重在250～300g雄性Wistar大鼠14只,随机分为两组。将代谢型谷氨酸受体(mGluRs)激动剂tACPD(实验组)及生理盐水(对照组)2μl注入右侧尾状核,6小时后观察动物旋转,在CT灌注成像检查后处死动物,测量左右尾状核干湿重提示脑组织含水量及光镜和电镜观察。结果实验组动物注射后6小时向对侧旋转,右侧尾状核水含量较对侧及对照组有显著性差异,P<0.05。CT灌注,实验组7例均可见脑局部rCBF明显下降,5例MTT及TTP延长,而rCBV仅有3例表现轻度下降。光镜HE染色及电镜组织学检查实验组可见星形细胞肿胀,小血管受压等改变。结论星形细胞肿胀可引起局部脑血流量下降,CT灌注成像可以清楚地显示由于星形细胞肿胀造成的局部脑血流动力学变化。

Objective To study the effects of astrocytic swelling on localcerebral blood flow. Methods 14 male Wistar rats, weighing 250~300g wererandomly divided into control and experimental groups. T microinjection oftACPD (agonist of mGluRs) was given to the right caudatum of the rats ofthe experimental group.6 hours later, the rotation rate of the rats wascounted for 5 minutes.The water content of the brain was determined withthe dry/wet weight method.Dynamic CT perfusion images were obtainedwith computer-aided mapping. Histopathological changes of cerebral tissuewere observed with both optic and electron microscopies. Results Brainedema was induced 6 hours after tACPD injection.Swelling of the astrocyteswas observed with optic and electron microscopies.CT perfusion imagesdemonstrated a decrease of rCBF in all the 7 rats of the experimental group,a slowdown of MTT and TTP in 5 rats out of the 7 and a decrease of rCBVin 3 rats out of the 7.There was statistically significant difference of brain watercontent and rotationary rate between the rats of the control and experimentalgroups(P<0.05). Conclusion Swelling of astrocytes can induce a decrease ofcerebral blood flow.[