Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, Canada.
J Neuroinflammation. 2009 Dec 23;6:39. doi: 10.1186/1742-2094-6-39.
Transplantation of neural progenitor cells (NPC) constitutes a putative therapeutic maneuver for use in treatment of neurodegenerative diseases. At present, effects of NPC transplantation in Alzheimer's disease (AD) brain are largely unknown and a primary objective of this work was to demonstrate possible efficacy of NPC administration in an animal model of AD. The benefits of transplantation could involve a spectrum of effects including replacement of endogenous neurons or by conferring neuroprotection with enhancement of neurotrophic factors or diminishing levels of neurotoxic agents. Since chronic inflammation is a characteristic property of AD brain, we considered that transplantation of NPC could have particular utility in inhibiting ongoing inflammatory reactivity. We have tested intrahippocampal transplantation of NPC for efficacy in attenuating inflammatory responses and for neuroprotection in beta-amyloid (Abeta1-42) peptide-injected rat hippocampus.
Spheres of neural progenitor cells were grown from dissociated telencephalon tissue of rat embryos. NPC were infected with lentiviral vector green fluorescent protein (GFP) with subsequent cell transplantation into rat hippocampus previously injected (3 d prior) with Abeta1-42 peptide or PBS control. Immunohistochemical analysis was carried out (7 d post-NPC transplantation, 10 d post-peptide/PBS injection) for GFP, microgliosis (Iba-1 marker), astrogliosis (GFAP marker), neuron viability (MAP-2 marker) and levels of the proinflammatory cytokine, TNF-alpha.
Successful infection of cultured NPC with lentiviral vector green fluorescent protein (GFP) was demonstrated prior to cell transplantation into rat hippocampus. In vivo, immunohistochemical staining showed migration of GFP-positive cells, in a region of dentate gyrus between Abeta1-42/PBS injection site and NPC transplantation site, was increased x2.8-fold with Abeta1-42 compared to PBS injection. Double immunostaining in peptide-injected brain indicated GFP association with nestin and GFAP, but not MAP-2. Cell-specific immunostaining showed marked increases in microgliosis and astrogliosis in Abeta1-42-injected brain (respective increases of x4.3- and x4.6-fold compared with PBS injection). NPC transplantation significantly reduced microgliosis (by 38%) but not astrogliosis in peptide-injected hippocampus. The proinflammatory cytokine TNF-alpha was elevated by 6.7-fold (peptide vs PBS injection) with NPC administration attenuating levels of TNF-alpha (by 40%). Peptide-injected brain demonstrated neuronal loss (MAP-2 staining reduced by 45% vs PBS injection) with NPC transplantation effective in conferring neuroprotection (26% recovery of neurons).
These findings indicate efficacy for NPC transplantation in an animal model of AD with effects consistent with cellular actions to attenuate inflammatory reactivity induced by intrahippocampal peptide injection.
神经祖细胞（NPC）的移植构成了治疗神经退行性疾病的潜在治疗手段。目前，NPC 移植在阿尔茨海默病（AD）大脑中的作用在很大程度上尚不清楚，本研究的主要目的是证明 NPC 给药在 AD 动物模型中的可能疗效。移植的益处可能包括一系列的效果，包括替代内源性神经元，或者通过增强神经营养因子或降低神经毒性物质的水平来提供神经保护。由于慢性炎症是 AD 大脑的特征性特征，我们认为 NPC 的移植可能特别有助于抑制持续的炎症反应。我们已经测试了 NPC 海马内移植以减轻炎症反应和β-淀粉样蛋白（Abeta1-42）肽注射大鼠海马中的神经保护作用。
从大鼠胚胎的大脑皮质组织中分离出 NPC 球体。用慢病毒载体 GFP 感染 NPC，然后将其移植到先前用 Abeta1-42 肽或 PBS 对照注射的大鼠海马体中。在 NPC 移植后 7 天（肽/PBS 注射后 10 天）进行 GFP、小胶质细胞增生（Iba-1 标志物）、星形胶质细胞增生（GFAP 标志物）、神经元存活（MAP-2 标志物）和促炎细胞因子 TNF-α水平的免疫组织化学分析。
在将培养的 NPC 移植到大鼠海马体之前，成功地用慢病毒载体 GFP 感染了 NPC。在体内，免疫组织化学染色显示，与 PBS 注射相比，Abeta1-42 注射部位和 NPC 移植部位之间的齿状回区域中 GFP 阳性细胞的迁移增加了 x2.8 倍。在肽注射的大脑中，双重免疫染色表明 GFP 与巢蛋白和 GFAP 相关，但与 MAP-2 不相关。细胞特异性免疫染色显示，Abeta1-42 注射的大脑中微胶质细胞增生和星形胶质细胞增生明显增加（分别比 PBS 注射增加 x4.3-和 x4.6 倍）。NPC 移植可显著减少肽注射海马体中的小胶质细胞增生（减少 38%），但不能减少星形胶质细胞增生。促炎细胞因子 TNF-α升高 6.7 倍（肽与 PBS 注射相比），NPC 给药可降低 TNF-α水平（降低 40%）。肽注射的大脑显示神经元丢失（MAP-2 染色减少 45%与 PBS 注射相比），NPC 移植可有效提供神经保护（神经元恢复 26%）。
这些发现表明 NPC 移植在 AD 动物模型中具有疗效，其作用与减轻海马内肽注射诱导的炎症反应的细胞作用一致。
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