Zhang Limei, Hernández Vito S, Estrada Felipe S, Luján Rafael
Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico.
Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico.
J Chem Neuroanat. 2014 Mar;56:45-57. doi: 10.1016/j.jchemneu.2014.02.002. Epub 2014 Mar 6.
Pilocarpine model for temporal lobe epilepsy has shown aberrant neurogenesis, but mainly restricted to the dentate gyrus (DG). Herein, by using a modified protocol, combining pilocarpine with ipratropium bromide, we unexpectedly observed a heretofore-unrecognized distinct cellular population expressing the neuroprogenitor marker doublecortin (DCX) on post insult days (PID) 10, 14 and 18, mainly located in the temporal segment of the hippocampal fissure (hf). Some of these DCX+ cells possessed high morphological complexity and seemed to disperse toward the CA fields. Next, we injected bromodeoxyuridine (BrdU) in early (PID 2-4) and delayed (PID 5-7) fashions and killed the rats 7-35 days later for immunohistochemical and anatomical analysis. Massive increase of BrdU labeling was found in the delayed group and the neural stem cell-specific marker nestin was highly expressed in the same narrow band on PID7, so was glial fibrillary acidic protein (GFAP). Using double labeling with BrdU and a mature neuron marker NeuN, we found discrete but clear BrdU+/NeuN+ double labeled cells in the Cornu Ammonis (CA) pyramidal cell layer on PID35. Based on immunohistochemical and anatomical observations, as well as time-course analysis of BrdU, nestin, GFAP, DCX and NeuN expressions in this population of cells located in/near hf, we wish to suggest that this structure harbors neurogenic niches, in addition of the possible dispersion of neuroprogenitors from subgranular niches to CA fields also revealed by this study. Our results support the few previous reports demonstrating hippocampal CA field neurogenesis in adult rats. Mechanistic basis of the phenomenon is discussed.
毛果芸香碱颞叶癫痫模型已显示出异常神经发生，但主要局限于齿状回（DG）。在此，通过使用一种改良方案，将毛果芸香碱与异丙托溴铵联合使用，我们意外地观察到在损伤后第10、14和18天，有一群迄今未被认识的独特细胞群表达神经前体细胞标志物双皮质素（DCX），主要位于海马裂（hf）的颞段。这些DCX+细胞中的一些具有高度复杂的形态，似乎向CA区扩散。接下来，我们以早期（损伤后第2 - 4天）和延迟（损伤后第5 - 7天）的方式注射溴脱氧尿苷（BrdU），并在7 - 35天后处死大鼠进行免疫组织化学和解剖学分析。在延迟组中发现BrdU标记大量增加，并且神经干细胞特异性标志物巢蛋白在损伤后第7天在同一窄带中高度表达，胶质纤维酸性蛋白（GFAP）也是如此。使用BrdU与成熟神经元标志物NeuN的双重标记，我们在损伤后第35天在海马角（CA）锥体细胞层中发现了离散但清晰的BrdU+/NeuN+双重标记细胞。基于免疫组织化学和解剖学观察，以及对位于hf内/附近的这群细胞中BrdU、巢蛋白、GFAP、DCX和NeuN表达的时间进程分析，我们希望提出，除了本研究还揭示的神经前体细胞可能从颗粒下生态位扩散到CA区外，该结构还存在神经发生生态位。我们的结果支持了之前少数几篇证明成年大鼠海马CA区神经发生的报道。并讨论了该现象的机制基础。
