白血病抑制因子降低AMPA受体在肌萎缩侧索硬化转基因G93AG1H小鼠脑干及感觉运动皮质的表达

Reduction of expression of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors in the brain stem and sensorimotor cortex of the SOD1^(G93AG1H) transgenic mouse model of amyotrophic lateral sclerosis induced by leukaemia inhibitory factor

目的:观察肌萎缩侧索硬化转基因SOD1G93AG1H小鼠脑干及感觉运动皮质的α-氨基-3-羟基-5-甲基-4-异唑丙酸(alpha鄄amino鄄3鄄hydroxy鄄5鄄methyl鄄4鄄isoxazolepropionicacid熏AMPA)受体在不同发病阶段的表达,明确白血病抑制因子是否能降低其表达及抑制其神经毒性。方法:实验于2004-07/2006-03在墨尔本大学及天津市第一中心医院完成。起源于B6SJL鄄TgN(SOD1鄄G93A),表达突变人类超氧化物歧化酶1基因的转基因小鼠60只,随机分为正常对照组,肌萎缩侧索硬化对照组,白血病抑制因子治疗组,每组20只,雌雄各10只。采用放射性配基结合实验分析方法检测AMPA受体在正常对照组熏肌萎缩侧索硬化对照组及白血病抑制因子治疗组小鼠脑干及感觉运动皮质的表达,用共焦计数系统计数。结果:60只小鼠均进入结果分析。①与正常对照组比较,肌萎缩侧索硬化对照组脑干运动神经元上的AMPA受体在出生后90d及120d分别增加到1.68倍及3.30倍(P均<0.01),而白血病抑制因子治疗组分别增加到1.16倍穴P>0.05雪及2.48倍(P<0.01)。白血病抑制因子治疗组AMPA受体在脑干运动皮质的表达和肌萎缩侧索硬化对照组对比明显降低(P<0.01)。②肌萎缩侧索硬化对照组感觉运动皮质运动神经元上的AMPA受体在出生后90d及120d分别增加到1.71倍及4.95倍(P均<0.01),而白血病抑制因子治疗组分别增加到1.18倍穴P>0.05雪及3.55倍(P<0.01)。白血病抑制因子治疗组AMPA受体在感觉运动皮质的表达和肌萎缩侧索硬化对照组对比明显降低(P<0.01)。结论:在疾病的中晚期,肌萎缩侧索硬化小鼠脑干及感觉运动皮质AMPA受体数目明显增加,与谷氨酸盐介导的运动神经元毒性作用有关。

AIM： To observe the expression of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid （AMPA） receptors in the brain stem and sensorimotor cortex of the SOD1G93AG1H （SOD1） transgenic mouse model of amyotrophic lateral sclerosis （ALS）, and identify whether leukaemia inhibitory factor （LIF） can reduce the expression and inhibit the neurotoxicity of AMPA receptors. METHODS： The experiment was performed at the University of Melbourne and Tianjin First Central Hospital from July 2004 to March 2006. Totally 60 transgenic mice resourced from B6SJL-TgN（SOD1-G93A） and expressed human mutation superoxide dismutase 1 gene were randomly assigned into normal control, ALS control and LIF treated groups with 10 males and 10 females mice in each group. Radioligand binding assay was carried out in this experiment to estimate the expression of AMPA receptors in brain stem and sensorimotor cortex in the normal control, ALS control and LIF treated groups. The number of AMPA receptors was calculated using the confocal counting system. RESULTS： A total of 60 mice were involved in the result analysis. ① Compared with the normal control group, at the time points of postnatal 90-day and 120-day, the number of AMPA receptors on the motor neurons of brain stem increased to 1.68 and 3.30 times in the ALS control group （P 〈 0.01）, 1.16 times （P 〉 0.05） and 2.48 times （P 〈 0.01） in the LIF treated group, respectively. Compared with the ALS control group, the expression of AMPA receptors in brain stem and sensorimotor cortex in the LIF treated group decreased significantly （P 〈 0.01）. ② The number of AMPA receptors on the motor neurons of motorsensory cortex increased to 1.71 times and 4.95 times in the ALS control group （P 〈 0.01）, while 1.18 times （P 〉 0.05） and 3.55 times （P 〈 0.01） in the LIF treated group, respectively at days 90 and 120 after birth. The expression of AMPA receptors obviously decreased in the sensorimotor cortex in the LIF treated group compared with the ALS control group （P 〈 0.01）. CONCLUSION： The number of AMPA receptors in the brain stem and sensorimotor cortex of ALS mice significantly enhances at the middle and late stages of this disease, which is associated with glutamate-mediated neurotoxicity to motor neurons.