喹啉酸所致Huntington病动物模型的建立及行为学和组织病理学研究

Establishment of animal model of Huntington disease by use of quinolinic acid and its ethological and histopathological observation

为了制作Huntington病(Huntington disease,HD)兴奋性动物模型,本文向大鼠纹状体内注射喹啉酸(quinolinic acid,QA),并观察了其行为学改变和纹状体内GABA能神经元数目的改变。采用立体定向手术向大鼠单侧纹状体内注入1μl240nmol/μl喹啉酸制作动物模型。手术后2周通过腹腔注射阿朴吗啡、旷场试验(open-field test)、Morris水迷宫实验观察和比较模型组大鼠与对照组大鼠的旋转行为、对新环境的探索行为、学习记忆能力的差异,并用免疫组化方法观察了纹状体钙结合蛋白Calbindin阳性细胞数的变化。结果显示:模型组大鼠经阿朴吗啡诱导出现转向损伤侧的旋转行为;旷场分析中模型鼠跨格次数、后腿站立次数及理毛次数减少(P<0.05),说明其对新环境的探索行为和适应能力下降;Morris水迷宫实验表明模型大鼠逃避潜伏期延长(P<0.05)、运动速度减慢(P<0.05)、对原平台所在象限记忆频度减低(P<0.05),说明模型大鼠学习记忆能力下降,空间参考记忆缺陷;免疫组化实验显示模型大鼠纹状体内钙结合蛋白Calbindin阳性细胞数减少。上述结果表明利用立体定向技术向大鼠单侧纹状体注射QA建立的HD动物模型可以表现出与HD相似的行为学和组织病理学改变,是一种可靠的HD兴奋性毒性模型。

To establish a rodent model of Huntington disease （HD） and observe the ethological changes as well as the change of the number of GABAergic neurons in the striatum of the rats, excitotoxie quinolinic acid （ QA, 240 nmol/1ml） was unilaterally injected into the right striatum of rats by stereotactic operation. Two weeks after operation, apomorpbine-induced rotation test, open-field test （OFT） and Morris water maze （MWM） test were performed to measure the induced rotation change, exploring ability to the new environment as well as the spatial learning and memory ability, respectively. The number of calbindin-positive neurons in the striatum was determined by immunohistoehemistry. The results showed that： in the apomorphine-induced rotation test, ipsilateral rotation was observed in the HD model rats; QA-induced HD model rats showed less climbing, rearing and glooming than the sham rats in the OFF （P 〈0.05） ; in the MWM test, the time taken for the QA-induced HD model rats to find the platform was prolonged （P 〈0.05 ）, but the velocity of swimming and the memory frequency of the original platform quadrant decreased （ P 〈 0.05 ）, indicating that the spatial learning ability declined significantly in the QA-induced HD model rats. The amount of calbindin-positive cells in the striatum of the QA-induced HD model rats decreased significantly （ P 〈 0.05 ）. The present results suggest that both of the ethological and histopathological changes in the QA-induced rodent model of HD are similar to the features of human HD and thus unilateral injection of QA in the striatum can be considered as a reliable method to make a rodent excitotoxic model of HD.