大脑皮层梗死后大继发鼠丘脑、中脑、脊髓和臂丛损害

Secondary lesions at the ipsilateral thalamus,midbrain and contralateral spinal cord,brachial plexus after motor-sensory cortex infarction in hypertensive rats.

目的观察实验性大脑皮层梗死后大鼠同侧丘脑、中脑及对侧颈髓、臂丛神经是否发生继发性损害。方法32只易卒中型肾血管性高血压大鼠(stroke-prone renovascular hypertensive rats,RHRSP)行右侧大脑中动脉皮层支闭塞(middle cerebralartery cortex occlusion,MCAO)术,另外32只暴露而不凝闭大脑中动脉,作为假手术组。分别于术后1、2、3、4周各组各时间点取8只大鼠处死取脑和脊髓,免疫组化方法检测梗死灶同侧丘脑腹后核、中脑黑质及对侧脊髓颈膨大前角微管相关蛋白2(microtubule associated protein 2,MAP2)、胶质原纤维酸性蛋白(glial fibrillary acid protein,GFAP)以及特殊染色检测对侧臂丛神经。结果与同期假手术组相比,MCAO术后各周梗死灶同侧丘脑腹后核、中脑黑质和对侧脊髓前角MAP2表达降低,GFAP表达增高(P<0.05);而对侧臂丛未见明显改变。结论同侧丘脑腹后核、中脑黑质及对侧脊髓前角神经元细胞在大脑皮层梗死后存在继发性损害,这可能是梗死后期神经功能恢复困难的重要因素之一。

Objective To investigate the secondary damage of the ipsilateral thalamus, midbrain and contralateral spinal cord, brachial plexus after experiment cerebral cortex infarction in hypertensive rats. Methods Stroke-prone renovascular hypertensive rats were randomly divided into two groups： Sham operation group and right middle cerebral artery cortex occlusion （MCAO） group. Each group had 32 rats. The model of MCAO was successfully duplicated in 32 stroke-prone renovascular hypertensive rats with electric coagulation. At the end of 1^st ,2^nd ,3^nt and 4^th week, the rats were killed and the brains and spinal cords were sectioned for immunohistochemistry analysis in order to determine the expression of microtubule associated protein 2 （MAP2） and glial fibrillary acid protein（GFAP） in the ipsilateral thalamus, midbrain and contralateral spinal cord. The myelin, axon and whole structure change of the contralateral brachial plexus were analysed using myelin staining, axon glycine-Ag staining and HE staining. Results MAP2 positive immunoreactivities of MCAO group were lower than those of sham operation group at the ipsilateral thalamus and midbrain at 1^st ,2^nd ,3^nt and 4^th week after MCAO（ P 〈 0. 05 ）. MAP2 positive signal values of MCAO group were lower than those of sham operation group at the contralateral anterior horn of the spinal cord at 2^nd, 3^nt and 4^th week after MCAO （P 〈0. 05 ）. GFAP positive immunoreactivities of MCAO group were higher than those of sham operation group at the ipsilateral thalamus, midbrain and contralateral anterior horn of the spinal cord at 1^st ,2^nd ,3^nt and 4^th week after MCAO（ P 〈0. 05 ）. There were no significant morphological changes in the myelin, axon and whole structure of contralateral brachial plexus between MCAO group and sham operation group. Conclusions Secondary damage and neuroglial proliferation were documented at the related sites in central nervous system remote from infarction after experimental cerebral motorsensory cortex infarction, which may contribute to slow neurological recovery at the late stage.