高血压大鼠脑白质病变中髓鞘和轴索改变

Alterations of myelin and axon in white matter lesions of hypertensive rats

目的探究高血压大鼠脑白质病变中轴索微结构的变化。方法 18只雄性Sprague-Dawley大鼠,随机分为假手术组(n=9)与手术组(n=9),手术组先行双肾双夹术制作易卒中型肾血管性高血压大鼠模型,12周后间隔1 d先后夹闭双侧颈总动脉。颈总动脉夹闭术后12周对大鼠进行水迷宫试验评价大鼠是否存在认知功能受损,组织病理学评价小血管病理学改变、脑白质病变、胶质细胞改变及轴索微结构的变化。结果水迷宫实验:手术组的逃避潜伏期较假手术组明显升高,穿越平台次数较假手术组明显降低,差异具有统计学意义(P<0.05)。手术组大鼠存在小动脉内膜增厚、管腔狭窄;手术组较假手术组有明显的脑白质病变,且伴有少突胶质细胞减少;手术组病变部位Caspr表达明显减少,病变周围髓鞘正常区域出现郎飞结长度增加、结侧区长度增加及直径增粗。结论脑白质病变过程同时存在轴索和髓鞘的损伤。

Objective Investigating alterations of axon microstructures in white matter lesions in a rat model of hypertension. Methods Eighteen male Sprague-Dawley rats were randomly divided into sham operation group(n=9)and operation group(n=9). Operation group received two kidneys two clips surgeries and bilateral common carotid arteries ligations. In the 12 thweek after common carotid arteries ligation, rats were evaluated by Morris Water Maze test and then sacrificed for evaluation of pathological features, including small arteries’ pathologies, white matter lesions, glia changes and axon micro organizations. Results Morris Water Maze test showed that escape latencies was significantly higher in operation group than in sham operation group. The number of times of cross-over cite in the target quadrant was significantly lower in the operation group than in sham operation group(P <0.05). Compared with sham operation group, operation group showed a series of pathological features, such as arteriosclerosis, leukoaraiosis, loss of oligodendrocyte and disorganized paranode. Conclusions White matter lesion is a chronic progressive disease which involves both demyelination and axon injuries.