组织学方法界定脑梗死缺血半暗带的可行性探讨

Research on availabilily of penumbra definition by using histological method and MRI

目的 探讨用组织学方法界定脑梗死患者脑组织缺血性半暗带的可行性。方法 对 7例脑梗死病例的尸检大脑进行MRI的T2 图像分析 ,并观察脑组织大 /小切片、神经元、小胶质细胞、星形细胞、血管、细胞骨架 (MAP2 、NF2 0 0 )以及部分细胞因子 ;按损伤程度将病灶分为 0～ 3区 ,研究不同区域的特点。结果 0区的神经元、胶质细胞和血管皆坏死 ,可出现嗜伊红神经元 ,细胞骨架消失 ;1区可见大量缺血的暗神经元及皱缩神经元 ,细胞骨架严重破坏 ,有小胶质细胞激活等炎细胞反应 ;2区可见部分缺血变化的神经元、暗神经元和形态正常的神经元 ,有星形细胞和小胶质细胞反应 ,细胞骨架正常或改变轻微 ;缺血 2d内 2区面积迅速减小 ,此时MRI显示的病灶小于组织大切片证实的病灶 ,只显示 0区和 1区病灶 ,不显示 2区病灶。 3区细胞形态正常 ,有小胶质细胞激活、星形细胞增生、转化生长因子 (TGF)表达增加以及肿瘤坏死因子α(TNFα)阳性表达 ,持续存在于全部病例的病灶周边。结论 0区、1区为中心坏死区。结合MRI、细胞和细胞骨架变化可以推断 ,2区为半暗带等值区 ;3区为损伤反应区 ,有些文献称之为“半暗带”。

Objective To prove whether it is availble to define the penumbra histopathologically and immunohistopathologically by observing the MRI T 2 imaging,cytoskeleton and neuron changing. Methods Seven cases of autopsy infarct brain with different ischemic time were studied in our program. By MRI T 2 imaging, the fixed brains were examined. Large section of whole brain, and small section of different parts,in and out of the infarct area, and the opposite hemisphere were observed. After observing the neuron, cytoskeleton, microglia, astrocyte, vessel, and also some cytokines by histological and immunohistochemical methods, we divide the ischemic and surrounding areas into four different parts as to seeing the different changes. Results In area 0, the neuron, gliocyte and vessel were all necrotic, eosinocytes developed, and cytoskeletons disappeared. In area 1, there were large number of dark neurons, shrinking cells with heavily destroyed, cytoskeleton, active microglia and inflammatory cells. In area 2, there were a few ischemic neurons , a few dark neurons, and normal neurons,and were also lots of active astrocyte and microglial. The proportion of area 2 was reduced sharply in two days. The ischemic proportion shown by MRI was smaller than that shown by large section of the whole brain. MRI T 2 imaging showed only the area 0 and area 1 with T 2 value increasing, and not showed the area 2 with normal T 2 value. In area 3, the cells were all in normal shape.However,the active microglia and astrocyte hyperplasia, together with the positive TGF β and TNFα expression, existed in area 3 in all seven brains.Conclusions Area 0 is the infracted mature area, area 1 is the irreversible area, both of them are centers of the necrotic area. Combined with MRI, neuron and cytoskeleton changes, we conclude that area 2 is the possible reversible damage area, or the equal area of penumbra. Area 3 is the response area to ischemic damage, which in some authors’studies was called‘penumbra’.