新生猪缺氧缺血性脑病早期弥散加权像变化及热休克蛋白70表达

Early Changes of Diffusion Weighted Imaging and Expression of Heat Shock Protein 70 in Newborn Pigs with Hypoxic-Ischemic Encephalopathy

目的探讨早期缺氧缺血性脑病(HIE)动物模型弥散加权像(DWI)变化和热休克蛋白(HSP)70表达的演变规律。方法3日龄新生猪19只随机分为正常对照组、假手术组、缺氧缺血组。用1.5T磁共振仪行DWI和T2WI检查;用表观弥散系数(ADC)图,测量病灶中心区和周边区ADC值;应用SP法计数中心区和周边区HSP70阳性细胞。结果缺氧缺血组出现四肢抽搐、角弓反张等体征。缺氧缺血后3 h DWI有高信号,ADC图有低信号。各组中心区与周边区ADC比较有显著差异(P<0.01)。缺氧缺血后3 h出现HSP70阳性细胞,6 h达高峰,之后逐渐下降,各组中心区和周边区HSP70阳性细胞计数比较有极显著差异(P<0.01)。结论DWI结合ADC值可以敏感而准确地显示HIE病灶;HSP70表达提示早期HIE病灶周边区有可逆的脑组织区域。

Objective To explore the regularity of the early findings with diffusion weighted imaging and apparent diffusion coefficient,as well as the expression of heal shock protein 70 （HSP 70） in newborn pigs with hypoxic-iscemic encephalopathy（HIE）, Methods Nineteen newborn pigs were divided into normal control group, sham operation group, and cerebral hypoxic-ischemic group.The model of cerebral hypoxic ischemia was made by occlusion of bilateral common carotid arter-ies, then inspiration of 3% oxygen for 30 minutes. T2-weighted imaging and diffusion-weighted imaging （DWI） were perforated on a 1.5 T Mignet scanner at varying time point. Apparent diffusion coefficient （ADC） values were measured in the central regions and peripheral regions of lesions, By means of SP immunoreactivity, the expression of HSP70 was examined. Results Abnormal signal intensity was detected on DWI and ADC maps in hypoxic-ischemic 3,6,24 hours groups. There were significant statistical differences （P〈0.01） between ADC values of the central regions and those of the peripheral regions. The expression of HSP70 was at a lower level at the 3 hours after HIE, and raised to the highest peak at the 6 hours, then rapidly decred. There were significant statistical difference between HSP70 expression in the central regions and those in peripheral regions in all groups（P〈0.01）, Conclusions Compared with T2WI, DWI and ADC maps can be used to identify early lesions, and improve conspicuity of hypoxic -ischemic injury. ADC values can be used as an objective measurement for hypoxic-ischemic injury. Cerebral tissue reversibility could be further reflected with the infomation of ADC values and HSP70 immunohistochemical staining.