Douen A G, Dong Li, Vanance S, Munger R, Hogan M J, Thompson C S, Hakim A M
Trillium Medical Centre, Mississauga, Ontario, Canada.
Brain Res. 2004 May 22;1008(2):139-46. doi: 10.1016/j.brainres.2003.08.070.
During embryogenesis, transient expression of nestin in proliferating neuroepithelial stem cells signals the commitment of progenitor cells to differentiate. Although adult mammalian brain contains very little nestin, significant upregulation of nestin has been reported following cerebral injury, leading to speculation that nestin may be involved in brain repair. In this study, we assessed the temporal profile of nestin expression following ablation injury of the sensory barrel cortex and investigated the influence of contralateral whisker stimulation on nestin expression. Since the adult mammalian brain contains proliferating neuronal progenitor cells that can be labeled with bromodeoxyuridine (BrdU), we also determined the association of nestin reexpression with BrdU-labeled cells. Nestin reexpression was detected predominantly in the ipsilateral cortex 3 days post-ablation. There was no significant nestin upregulation in the subcortical region. Nestin reexpression was most marked surrounding the lesion, but also extended throughout the entire lateral cortex. Nestin in the ipsilateral cortex subsided by day 7, although perilesional nestin expression was still apparent 28 days post-injury. Western blot analysis of nestin expression 3 days post-ablation confirmed a significant two-fold increase in nestin expression (p<0.05). Double immunofluorescence labeling demonstrated that the majority of nestin expression occurred in astrocytes. We were unable to detect any colocalization with neuronal makers. However, BrdU-labeled cells, which were readily detected in the subventricular zone prior to injury, were readily detected in the perilesional area 3 days post-ablation, concomitant with nestin in this area. Confocal microscopy detected several BrdU-positive cells expressing nestin. Taken together, the data support a potential role for nestin reexpression in brain repair.
在胚胎发育过程中,巢蛋白在增殖的神经上皮干细胞中的瞬时表达标志着祖细胞开始分化。尽管成年哺乳动物大脑中巢蛋白含量极少,但据报道,脑损伤后巢蛋白会显著上调,这引发了人们对巢蛋白可能参与脑修复的猜测。在本研究中,我们评估了感觉桶状皮层消融损伤后巢蛋白表达的时间变化,并研究了对侧触须刺激对巢蛋白表达的影响。由于成年哺乳动物大脑中含有可被溴脱氧尿苷(BrdU)标记的增殖神经元祖细胞,我们还确定了巢蛋白重新表达与BrdU标记细胞的关联。消融后3天,主要在同侧皮层检测到巢蛋白重新表达。皮层下区域巢蛋白无明显上调。巢蛋白重新表达在损伤部位周围最为明显,但也延伸至整个外侧皮层。同侧皮层中的巢蛋白在第7天消退,尽管损伤后28天损伤周围的巢蛋白表达仍很明显。消融后3天对巢蛋白表达进行的蛋白质印迹分析证实,巢蛋白表达显著增加了两倍(p<0.05)。双重免疫荧光标记表明,大多数巢蛋白表达发生在星形胶质细胞中。我们未能检测到与神经元标志物的任何共定位。然而,损伤前在脑室下区容易检测到的BrdU标记细胞,在消融后3天在损伤周围区域很容易检测到,且与该区域的巢蛋白共存。共聚焦显微镜检测到几个表达巢蛋白的BrdU阳性细胞。综上所述,这些数据支持巢蛋白重新表达在脑修复中的潜在作用。