摘要
局灶性脑缺血模型是研究缺血性脑血管病的重要模型.目前国外用血管内栓线技术建立的局灶性脑缺血大鼠模型存在两方面的不足:(1)栓线所用4-0外科缝线较软,手术前需经专门处理,使实验程序繁琐;(2)由于大鼠存在年龄、体重以及种族的差异,使用统一栓线往往造成受累脑组织缺血程度不一.我们采用不同直径(1.2号、1.5号、2.0号)和不同长度(1.5—2. 5cm)的市售单股尼龙线与不同年龄、体重的成年SD大鼠匹配使用,建立了恒定的大脑中动脉梗塞(MCAO)模型,实验证明该模型可靠性和重复性好.
The focal cerebral ischemic model is a important model in studing ischemic cerebral vascular diseases. The preliminary experiments were performed without cranietomy based on advancing an intraluminal suture perforated the ICA.This model showed two shortcomings: (1) due to softer 4 - 0 nylon suture, it had to be coated with silicone, mixed with a hardener before operation and (2) this model showed a substantial variability of cerebral infarction volume and size. We used monofilament nylon thread (rather than surgical suture) in varying thread size (1.2# ,1.5# and 2.0# ) and length of thread (1.5-2.5cm) for varying rat weight (250-400 grams) so that we produced a reliable and reversible middle cerebral artery occlusion model (MCAO). Adult male Sprague-Dawley rats underwent 30min,90 min, 3 and 6 hours of MCAO followed by 1,3 and 16 days of reperfusion. The experiment showed that this nylon thread had no direct mechanical damage to occluded vascular wall and inducing adhesion because the lumen of MCA and circle of Willis were clearly washed by the transcardiac perfusion with normal saline before sacrifice. The neurologic finding were scored on a five-point scale.Except for one that had no neurologic deficit after MCAO and two that died of epilepsy, all rats exhibited neurologic deficits by a score 1 to 4. In TTC-stained coronal brain slices, there were a consistant infarcted areas in the frontoparietal cortex, lateral segment of caudate putamen and to a varying extent in the medial segment of the caudate putamen. The histologic examination showed no remarkebly pathologic alterations in the rats with 30 min of MCA occlusion. There were cell edema and chromatin condensation and gliosis after 90 min of MCA occlusion. Light microscopy revealed a typical ischemic changes, characterized by most neurons shrunken and triangular with dark-stained nuclei in the brain of rats subjected to 3 hours of MCA occlusion. The irreversible changes of neuron were observed in infarcted area as well as its periphery at 6 hours after the onset of occlusion. The morphology is characterized by severe cell shrinkage, nuclear pyknosis, edema of white matter and softening of brain.We conclude that it is highly important to adjust the diameter andlength of thread inserted to various rat weight in producing a stableand reliable focal cerebral ischemic model.
基金
国家自然科学基金资助
关键词
动物模型
局灶性
脑缺血
栓线技术
model
focal cerebral ischemia
intraluminal suture technique