兔早期缺血性脑梗死后氮-乙酰天门冬氨酸含量和组织病理学之间的对照研究

目的:探讨早期兔大脑中动脉阻塞(MCAO)后脑内氮-乙酰天门冬氨酸(Naa)含量的动态演变规律及其与光镜、电镜下梗死脑组织相应病理变化之间的关系。方法:新西兰大白兔16只,磁共振波谱(MRS)检查组8只,病理学检查组8只。2组动物均经眶电凝阻断大脑中动脉(MCA),并分别在模型建立前及建立后0.5h、1h、2h、4h、6h、8h、12h和24h进行MRS和HE染色光镜和铅铀染色电镜检查。结果:MCAO后0.5hNaa即开始下降,随后6h内,Naa在此较低水平保持相对稳定;MCAO后6h,Naa再次明显下降。光镜下MCAO后2h神经元核固缩,6h细胞核固缩呈不规则形,神经元数目开始减少,12h部分神经元细胞核消失,神经元数量进一步减少,24h神经元坏死,神经元数量明显减少。电镜下MCAO后2h线粒体肿胀、嵴消失,6h神经元细胞质高度水肿,12h神经元围围明显水肿,24h神经元细胞膜和核膜崩解。结论:脑梗死急性期Naa下降可客观真实地反映存活神经元的数量或神经元密度。

An comparative research of Naa and pathology with acute ischemic infarction in rabbits

Objective: To observe the Naa evolution of early cerebral infarction in rabbit model of the middle cerebral artery occlusion (MCAO),and compared with pathomorphology by using light microscopy and electrical microscopy. Methods: 16 New Zealand rabbits were randomized into two groups, 8 rabbits were included in the MRS group and 8 rabbits were classified as histopathologic group. The MRS group was examined by MRI scanner before operation as well as at 0.5h, 1h, 2h, 4h, 6h, 8h, 12h and 24h after operation. The histopathologic group was observed by light microscopy and electrical microscopy. Results: Naa reduced at 0.5h, and was relative steady within subsequently 6 hours. Within 6h～24h, Naa was continuously decreased. Light microscopy revealed karyopyknosis in neural cells at 2h, karyopyknosis more irregular in neural cells at 6h, and neural cells number began to decrease, partial of the neural cell nuclei were disappeared and neural cells number decreased again on 12h, neural cells necrosis and neural cells number decreased dramatically at 24h. Electrical microscopy showed mitochondrial swelling obviously at 2h, and the neural cells demonstrated edema severely at 6h, edema around the neural cells at 12h, disintegration of the nuclear membranes and neural cell membranes at 24h. Conclusion: Naa decreased in early cerebral ischemic infarction could actually reflect quantity or density of the lively neural cell.