REDUCED BRANCHING AND LENGTH OF DENDRITES DETECTED IN CERVICAL SPINAL-CORD MOTONEURONS OF WOBBLER MOUSE, A MODEL FOR INHERITED MOTONEURON DISEASE
REDUCED BRANCHING AND LENGTH OF DENDRITES DETECTED IN CERVICAL SPINAL-CORD MOTONEURONS OF WOBBLER MOUSE, A MODEL FOR INHERITED MOTONEURON DISEASE
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DOI：
10.1002/cne.903110204
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发表时间：
1991-09-08
影响因子：
2.5
通讯作者：
VACCAGALLOWAY, LL
中科院分区：
文献类型：
--
作者：
MA, WY;VACCAGALLOWAY, LL
Wobbler小鼠（wr）已被提出作为人类遗传性运动神经元疾病（婴儿脊髓性肌萎缩症）的模型。主要的缺陷被认为是在运动神经元。因此，我们对与年龄和性别匹配的正常表型（NFR/wr）幼崽相比，在运动神经元疾病晚期，Wobbler小鼠颈椎运动神经元发生的定性和定量变化进行了调查。采用快速高尔基法。在对照小鼠和Wobbler小鼠中，根据树突模式确定了四种类型的神经元：多极、三极、双极和单极细胞。单极细胞在Wobbler标本中比对照中更常被观察到，并且可能代表了具有更多初级树突的其他细胞类型退化的最后阶段。中等（300-999 μ -m2）和大（1000 μ -m2）浸渍的神经元（可能是α -运动神经元）显示出强烈的细胞退化迹象，包括树突长度、分布、分支以及棘数的测量在统计上显着减少。相比之下，小（< 300 mu-m2）神经元仅表现出轻微的退化迹象，包括树突长度轻微减少，但树突的分布和分支以及棘的数量没有明显差异。相反，可以检测到从小神经元发出的初级和次级树突分支的数量以及树突棘的数量有小幅增加。这些发现表明，发芽可能在一定程度上发生。虽然先前的研究表明，运动神经元的肿胀和随后的空泡化是Wobbler病的主要特征，但对Wobbler标本中浸渍神经元计算的平均体细胞面积（mu-m2）与对照组没有显着差异。据推测，Wobbler运动神经元病的晚期症状主要反映在中、大α运动神经元的树突和棘的变性。小的神经元（可能是运动神经元、中间神经元和伦肖细胞的混合种群）拥有树突和棘，似乎受到的影响较小，相反，它们显示出发芽的迹象。
The Wobbler mouse (wr) has been proposed as a model for human inherited motoneuron disease (infantile spinal muscular atrophy). The primary defect is thought to be in the motoneurons. Therefore we undertook a survey of the qualitative and quantitative changes occurring in the cervical spinal motoneurons of Wobbler mice during a late stage of the motoneuron disease compared with age- and sex-matched normal phenotype (NFR/wr) littermates. The Rapid Golgi Method was applied. In control and Wobbler mice, four types of neurons were identified according to their dendritic patterns: multipolar, tripolar, bipolar, and unipolar cells. Unipolar cells were observed more often in the Wobbler specimens than the controls and may represent a final stage in the degeneration of other cell types with greater numbers of primary dendrites. Medium (300-999-mu-m2) and large (> 1,000-mu-m2) impregnated neurons (presumably alpha-motoneurons) showed strong indications of cell degeneration, including statistically significant reductions in the measurements for dendritic length, distribution, and branching, as well as the number of spines. In contrast, the small (< 300-mu-m2) neurons showed only mild signs of degeneration, including slight reductions in dendritic length, but no significant differences appeared in the distribution and branching of dendrites, or in the number of spines. Instead, a small increase could be detected in the number of primary and secondary dendritic branches emanating from the small neurons, as well as in the number of dendritic spines. These findings suggest that sprouting may occur to a slight extent. Although previous studies document that swelling with subsequent vacuolation of motoneurons is the predominant feature characterizing the Wobbler disease, the mean soma area (mu-m2) calculated for the impregnated neurons of the Wobbler specimens showed no significant difference from the controls. It is hypothesized that the advanced signs of the Wobbler motoneuron disease are primarily reflected in the degeneration of the dendrites and spines on the medium and large alpha-motoneurons. The small neurons (presumably a mixed population of gamma-motoneurons, interneurons, and Renshaw cells) possess dendrites and spines that seem to be less affected, and instead show signs of sprouting.