缺血性脑梗塞CT表现与梗塞后神经细胞凋亡及坏死的相关性

CT findings of ischemic infarction in relation to neuronal damage in rabbits

目的探讨实验性缺血性脑梗塞早期CT表现与神经细胞损伤的相关性及与临床诊断、治疗、预后的关系.方法将新西兰大白兔经颈总动脉注入PVA栓子栓塞大脑中动脉,在不同的时间点(2～36 h)对兔脑进行CT扫描,并取脑组织经HE染色、Nissle染色、免疫组化(TUNEL法)进行观察.结果CT分期Ⅰ期(脑梗塞后2～8 h),神经细胞首先出现缺血改变,随后细胞周围出现水肿;基底节周围及大脑皮质可见少量TUNEL阳性细胞.CT分期Ⅱ期(梗塞后12～18 h),以神经细胞溶解消失为主;基底节周围及大脑皮质可见较多TUNEL阳性细胞.CT分期Ⅲ期(梗塞后24～36h),脑水肿改变十分显著,基底节呈明显的坏死区,神经细胞坏死,结构消失,大脑皮质可见大量TUNEL阳性细胞.神经元具有凋亡及坏死的双重形态学特征.结论缺血性脑梗塞后神经细胞损伤形态上有水肿、凋亡及坏死等多样性,CT扫描显示缺血性脑梗塞的进展与实际病理变化有高度相关性.

Objective To explore the early changes in CT findings of ischemic infarction in relation to neuronal damage in rabbits. Methods Thirty-two rabbits were divided into control group and experiment groups and scanned with CT 2, 4, 8, 12, 18, 24, and 36 h after ischemic cerebral infarction induced by PVA embolization of the middle cerebral artery (MCA), respecti- vely. The brain specimen were stained with HE, Nissle and TUNEL techniques for pathological examination. Results In stage Ⅰ (2-8 h after MCA occlusion) by CT staging, the neurons exhibited ischemic change followed by cell edema. A small number of TUNEL-positive cells were found in the basal ganglia and cortex. In stage Ⅱ (12-18 h after MCA occlusion), neuronal swelling and lysis were observed with greater number of TUNEL-positive neurons in the basal ganglia and cortex. In stage Ⅲ ( 24-36 h after MCA obstruction), cerebral edema became obvious and ischemic cores were distinct, with numerous necrotic neurons seen and destruction of the cell structure. Numerous TUNEL-positive cells were seen in the ischemic penumbra and cortex. Conclusion The damaged neurons after ischemic cerebral infarction showed varied morphology including cell edema, apoptosis, necrosis, and necrosis-apoptosis continuum. CT manifestations are strongly associated with the progression of ischemia and the pathological changes.