改良光化学栓塞法诱导缺血性脑卒中模型大鼠的病理变化

Pathological changes in rats with ischemic stroke induced by improved photochemical embolization

背景:大鼠光化学栓塞模型可以良好地模拟缺血性卒中,具有损伤脑区特异性、高重复性及低死亡率等优势,但光源的选择及玫瑰红注射浓度等多个条件都会影响造模的结果,需要后期进行细致的评估来确定造模的成功。目的:建立稳定、不易自发恢复的大鼠缺血性脑卒中模型,并探究卒中区域的病理变化及大鼠行为学变化。方法:雄性Wistar大鼠52只随机被分为假手术组6只、光化学栓塞组46只。光化学栓塞组取18只分别于大鼠股静脉注射20,40及80 mg/kg玫瑰红制作光化学栓塞模型,筛选出造模最佳的玫瑰红浓度;再对剩余28只大鼠进行光化学栓塞造模手术;假手术组大鼠不进行激光器定点照射及不注射玫瑰红染料。术后1 d利用TTC染色揭示在不同玫瑰红浓度注射下梗死范围的变化;对大鼠光化学栓塞后1,3,7,14 d运用NeuN染色观察梗死区域内神经元的死亡情况;Iba-1,GFAP,GLUT-1染色观察光化学栓塞后卒中区域炎症反应、胶质瘢痕及血管的变化;应用圆柱体实验及网格错误实验评价大鼠光化学栓塞后行为学的变化。结果与结论:(1)80 mg/kg的玫瑰红浓度引起的卒中腔体积最大,光化学栓塞模型重复性高,动物死亡率低,7 d可以形成较稳定的卒中腔;(2)光化学栓塞后在7 d可以形成相对稳定的胶质瘢痕带,但炎症反应在1-14 d逐渐加重;(3)光化学栓塞减少卒中腔附近的血管面积,并在14 d趋于稳定;(4)光化学栓塞后大鼠出现长期的感觉及运动功能下降;(5)结果表明大鼠光化学栓塞模型稳定良好,不易自发恢复,适合缺血性脑卒中病理变化的研究。

BACKGROUND:A rat model of photochemical embolization can simulate ischemic stroke well,with the advantages of specific damage to the brain area,high reproducibility and low mortality.However,the choice of light source and the concentration of rose bengal injection have certain effects on the model.So,a detailed evaluation is needed to determine whether the animal model is established successfully.OBJECTIVE:To establish a stable model of ischemic stroke in rats that is less liable to recover spontaneously,and to explore the pathological changes in the infarct region and behavior changes in rats.METHODS:A total of 52 male Wistar rats were randomly divided into sham operation group(n=6)and photochemical embolization group(n=46).In the photochemical embolization group,20,40,and 80 mg/kg rose bengal was injected into the rat femoral vein to make photochemical embolization models,and meanwhile the optimal rose bengal concentration was screened out.The remaining 28 rats were subjected to photochemical embolization.Rats in the sham operation group were not irradiated with laser and were not injected with rose bengal dye.TTC staining was used to reveal the changes in infarct size at 1 day after injection with different concentrations of rose bengal.NeuN staining was used to observe neuronal death in the infarct region at 1,3,7,and 14 days after photochemical embolization.Iba-1,GFAP,and GLUT-1 staining were employed to observe the changes of inflammatory responses,glial scars and blood vessels in the infarct region after photochemical embolization.Cylinder experiment and grid error experiment were used to evaluate the behavioral changes of rats after photochemical embolization.RESULTS AND CONCLUSION:Injection with 80 mg/kg rose bengal caused the largest size of stroke cavity,resulting in a high reproducibility and a low animal mortality.A stable stroke cavity could be formed within 7 days after injection.Relatively stable glial scar zone formed at 7 days after photochemical embolization,but inflammatory reactions gradually aggravated in 1-14 days.Photochemical embolization reduced the area of blood vessels near the stroke cavity,and the area tended to be stable at 14 days.The rats experienced long-term decline in sensation and motor function after photochemical embolization.To conclude,the rat model of photochemical embolization is stable and not easy to recover spontaneously,which is suitable for studying the pathological changes after ischemic stroke.