Glycinergic Innervation of Motoneurons Is Deficient in Amyotrophic Lateral Sclerosis Mice A Quantitative Confocal Analysis
Glycinergic Innervation of Motoneurons Is Deficient in Amyotrophic Lateral Sclerosis Mice A Quantitative Confocal Analysis
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DOI：
10.2353/ajpath.2009.080557
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发表时间：
2009-02-01
影响因子：
6
通讯作者：
Martin, Lee J.
中科院分区：
文献类型：
--
作者：
Chang, Qing;Martin, Lee J.
运动神经元兴奋性改变与肌萎缩侧索硬化病理生物学有关。为了验证在肌萎缩侧索硬化小鼠模型中脊髓运动神经元的抑制性中间神经元神经支配异常的假设，我们测量了不同年龄的表达其突变形式的人超氧化物歧化酶-1与Gly 93-> Ala取代（G93 A-SOD 1）的小鼠和对照组的脊髓运动神经元上的GABA能、甘氨酸能和胆碱能免疫反应终末。谷氨酸脱羧酶、甘氨酸转运蛋白-2和胆碱乙酰转移酶分别用作GABA能、甘氨酸能和胆碱能末梢的标记物。通过共聚焦显微镜观察和定量分析三重免疫荧光标记的终扣接触运动神经元。与对照组相比，G93 A-SOD 1小鼠外侧运动神经元上的甘氨酸转运体-2-bouton密度显著降低。这种减少在6周龄时不存在，但在无症状的8周龄小鼠中存在，并随着1.2至14周龄的疾病进展而恶化。运动神经元失去了大多数甘氨酸能神经支配的16周龄（终末期）时，有一个显着减少的运动神经元和胆碱乙酰转移酶阳性终扣的数量。G93 A-SOD 1小鼠的谷氨酸脱羧酶-bouton密度无显著差异。甘氨酸能神经支配的减少先于线粒体肿胀和空泡化。在G93 A-SOD 1小鼠中，钙结合蛋白阳性Renshaw细胞数量在12周龄时显著减少。因此，在肌萎缩侧索硬化症中，运动神经元功能的抑制性甘氨酸调节的选择性丧失或甘氨酸能中间神经元变性导致运动神经元变性。(Am J Pathol 2009，174：574-585; DOI：10.2353/ajpath.2009.080557）
Altered motoneuron excitability is involved in amyotrophic lateral sclerosis pathobiology. To test the hypothesis that inhibitory interneuron innervation of spinal motoneurons is abnormal in an amyotrophic lateral sclerosis mouse model, we measured GABAergic, glycinergic, and cholinergic immunoreactive terminals on spinal motoneurons in mice expressing it mutant form of human superoxide dismutase-1 with a Gly93 -> Ala substitution (G93A-SOD1) and in controls at different ages. Glutamic acid decarboxylase, glycine transporter-2, and choline acetyltransferase were used as markers for GABAergic, glycinergic, and cholinergic terminals, respectively. Triple immunofluorescent labeling of boutons contacting motoneurons was visualized by confocal microscopy and analyzed quantitatively. Glycine transporter-2-bouton density on lateral motoneurons was decreased significantly in G93A-SOD1 mice compared with controls. This reduction was absent at 6 weeks of age but present in asymptomatic 8-week-old mice and worsened with disease progression from 1.2 to 14 weeks of age. Motoneurons lost most glycinergic innervation by 16 weeks of age (end-stage) when there was; a significant decrease in the numbers of motoneurons and choline acetyltransferase-positive boutons. No significant differences in glutamic acid decarboxylase-bouton densities were found in G93A-SOD1 mice. Reduction of glycinergic innervation preceded mitochondrial swelling and vacuolization. Calbindin-positive Renshaw cell number was decreased significantly at 12 weeks of age in G93A-SOD1 mice. Thus, either the selective loss of inhibitory glycinergic regulation of motoneuron function or glycinergic interneuron degeneration contributes to motoneuron degeneration in amyotrophic lateral sclerosis. (Am J Pathol 2009, 174:574-585; DOI: 10.2353/ajpath.2009.080557)