Laboratorio de Citoarquitectura y Plasticidad Neuronal, Instituto de Investigaciones cardiológicas Prof. Dr. Alberto C. Taquini (ININCA), Facultad de Medicina, UBA-CONICET, Marcelo T. de Alvear 2270, C1122AAJ, Buenos Aires, Argentina.
Synapse. 2012 Jan;66(1):9-19. doi: 10.1002/syn.20978. Epub 2011 Oct 11.
Perinatal asphyxia (PA) is a medical condition associated with a high short-term morbimortality and different long-term neurological diseases. In previous works, we have shown that neuronal and synaptic changes in rat striatum lead to ubi-protein accumulation in post-synaptic density (PSD) after six months of sub-severe PA. However, very little is known about the synaptic and related structural modifications induced by PA in young rats. In the present work, we studied neuronal cytoskeleton modifications in striatum induced by subsevere PA in 30-day-old rats. We observed a significant decrease in the number of neurons, in particular calbindin immunoreactive neurons after PA. In addition, it was also observed that actin cytoskeleton was highly modified in the PSD as well as an increment of F-actin staining by Phalloidin-alexa(488) in the striatum of PA rats. Using correlative fluorescence-electron microscopy photooxidation, we confirmed and extended confocal observations. F-actin staining augmentation was mostly related with an increment in the number of mushroom-shaped spines. Consistent with microscopic data, Western blot analysis revealed a β-actin increment in PSD in PA rats. On the other hand, MAP-2 immunostaining was decreased after PA, being NF-200 expression unmodified. Although neuronal death was observed, signs of generalized neurodegeneration were absent. Taken together these results showed early post-synaptic F-actin cytoskeleton changes induced by PA with slightly modifications in the other components of the neuronal cytoskeleton, suggesting that F-actin accumulation in the dendritic spines could be involved in the neuronal loss induced by PA.
围产期窒息（PA）是一种与短期高发病率和死亡率以及不同长期神经疾病相关的医学病症。在之前的研究中，我们已经表明，大鼠纹状体中的神经元和突触变化导致亚重度 PA 六个月后突触后密度（PSD）中 ubi-蛋白积累。然而，对于 PA 引起的年轻大鼠突触和相关结构的改变，人们知之甚少。在本工作中，我们研究了亚重度 PA 对 30 日龄大鼠纹状体中神经元细胞骨架的影响。我们观察到 PA 后神经元数量，特别是 calbindin 免疫反应性神经元数量显著减少。此外，还观察到 PSD 中的肌动蛋白细胞骨架高度改变，以及 Phalloidin-alexa（488）在 PA 大鼠纹状体中的 F-肌动蛋白染色增加。通过相关荧光电子显微镜光氧化，我们证实并扩展了共聚焦观察。F-肌动蛋白染色增加主要与蘑菇状棘突数量的增加有关。与显微镜数据一致，Western blot 分析显示 PA 大鼠 PSD 中β-肌动蛋白增加。另一方面，PA 后 MAP-2 免疫染色减少，NF-200 表达不变。尽管观察到神经元死亡，但不存在广泛的神经退行性改变的迹象。总之，这些结果表明 PA 早期诱导了突触后 F-肌动蛋白细胞骨架的变化，而神经元细胞骨架的其他成分仅有轻微改变，提示 F-肌动蛋白在树突棘中的积累可能参与了 PA 引起的神经元丢失。
