Centre of Molecular Biology and Neuroscience (CMBN), University of Oslo, P.O. Box 1105 Blindern, NO-0317 Oslo, Norway.
Brain Res. 2011 Mar 10;1378:105-18. doi: 10.1016/j.brainres.2010.12.090. Epub 2011 Jan 12.
Parkinson's disease (PD) is a neurodegenerative disorder characterized by a preferential loss of dopaminergic (DAergic) neurons of the substantia nigra pars compacta (SNpc). Both glial cell line-derived neurotrophic factor (GDNF) and brain-derived neurotrophic factor (BDNF) play key roles in maintaining the DAergic phenotype and exert a cytoprotective effect on these neurons in vivo and in vitro. However, controversy still exists regarding the relative potency of the two factors and the extent to which they act synergistically. In this study, we used a refined version of organotypic cultures as a model for PD. The neurotoxin 6-hydroxydopamine (6-OHDA) was applied unilaterally in slices of rat mesencephalon, allowing for internal controls and enabling a precise comparison between the two sides of the midbrain. We evaluated the cytoprotective and regenerative effects of BDNF, GDNF and the combination of these in terms of surviving tyrosine hydroxylase positive (TH+) cells and TH mRNA expression. Pre-, co-, or post-treatment with neurotrophic factors clearly protects DAergic neurons from cell death. Cell survival is particularly pronounced in cultures pre-treated with BDNF and is not further increased when BDNF is applied in combination with GDNF in equimolar dose. On the lesion side, surviving TH+ cells exposed to neurotrophic factors showed extensive sprouting, and BDNF treatment resulted in a two-fold increase in TH mRNA. Such effects were not seen in the absence of toxin exposure. Thus, we observed that BDNF induced an upregulation of the DAergic phenotype, which suggest a cytoprotective and regenerative effect.
帕金森病（PD）是一种神经退行性疾病，其特征是黑质致密部（SNpc）中的多巴胺能（DAergic）神经元优先丧失。胶质细胞系衍生的神经营养因子（GDNF）和脑源性神经营养因子（BDNF）在维持 DAergic 表型方面都起着关键作用，并在体内和体外对这些神经元发挥细胞保护作用。然而，关于这两种因子的相对效力以及它们协同作用的程度，仍存在争议。在这项研究中，我们使用改良的器官型培养作为 PD 模型。神经毒素 6-羟多巴胺（6-OHDA）被应用于大鼠中脑切片的单侧，允许进行内部对照，并能够精确比较中脑的两侧。我们根据酪氨酸羟化酶阳性（TH+）细胞的存活和 TH mRNA 表达来评估 BDNF、GDNF 及其组合的细胞保护和再生作用。神经营养因子的预、共或后处理明显保护 DAergic 神经元免受细胞死亡。细胞存活在预先用 BDNF 处理的培养物中尤为明显，当 BDNF 与等摩尔剂量的 GDNF 联合应用时，不会进一步增加。在损伤侧，暴露于神经营养因子的存活 TH+细胞表现出广泛的发芽，BDNF 处理导致 TH mRNA 增加两倍。在没有毒素暴露的情况下，没有观察到这种效果。因此，我们观察到 BDNF 诱导了 DAergic 表型的上调，这表明了细胞保护和再生作用。
