Argandoña Enrike G, Rossi Marco L, Lafuente Jose V
Department of Nursing I, School of Nursing, Euskal Herriko Unibertsitatea/University of the Basque Country, Leioako Campusa, Leioa E-48940, Spain.
Brain Res Dev Brain Res. 2003 Mar 14;141(1-2):63-9. doi: 10.1016/s0165-3806(02)00643-0.
After birth, exposure to visual inputs modulates cortical development, inducing numerous changes of all components of the visual cortex. Most of the cortical changes thus induced occur during what is called the critical period. Astrocytes play an important role in the development, maintenance and plasticity of the cortex, as well as in the structure and function of the vascular network. Dark-reared Sprague-Dawley rats and age-matched controls sampled at 14, 21, 28, 35, 42, 49, 56 and 63 days postnatal (dpn) were studied in order to elucidate quantitative differences in the number of positive cells in the striate cortex. The astrocytic population was estimated by immunohistochemistry for S-100beta protein. The same quantification was also performed in a nonsensory area, the retrosplenial granular cortex. S-100beta positive cells had adult morphology in the visual cortex at 14 dpn and their numbers were not significantly different in light-exposed and nonexposed rats up to 35 dpn, and were even higher in dark-reared rats at 21 dpn. However, significant quantitative changes were recorded after the beginning of the critical period. The main finding of the present study was the significantly lower astroglial density estimated in the visual cortex of dark-reared rats over 35 dpn as well as the lack of difference at previous ages. Our results also showed that there were no differences when comparing the measurements from a nonsensory area between both groups. This led us to postulate that the astrocytic population in the visual cortex is downregulated by the lack of visual experience.
出生后，视觉输入的暴露会调节皮质发育，引发视觉皮质所有组成部分的众多变化。如此诱导产生的大多数皮质变化发生在所谓的关键期。星形胶质细胞在皮质的发育、维持和可塑性以及血管网络的结构和功能中发挥着重要作用。为了阐明纹状皮质中阳性细胞数量的定量差异，对出生后14、21、28、35、42、49、56和63天（dpn）的暗饲养斯普拉格-道利大鼠和年龄匹配的对照进行了研究。通过免疫组织化学检测S-100β蛋白来估计星形胶质细胞群体。在一个非感觉区域，即脾后颗粒皮质，也进行了同样的定量分析。S-100β阳性细胞在14 dpn时在视觉皮质中具有成年形态，在35 dpn之前，光暴露和未暴露大鼠中的细胞数量没有显著差异，在21 dpn时，暗饲养大鼠中的细胞数量甚至更高。然而，在关键期开始后记录到了显著的定量变化。本研究的主要发现是，在35 dpn以上的暗饲养大鼠视觉皮质中估计的星形胶质细胞密度显著较低，而在之前的年龄没有差异。我们的结果还表明，两组在非感觉区域的测量结果进行比较时没有差异。这使我们推测，视觉皮质中的星形胶质细胞群体因缺乏视觉经验而下调。
