Das K P, Chao S L, White L D, Haines W T, Harry G J, Tilson H A, Barone S
Neurotoxicology Division, Cellular and Molecular Toxicology Branch, National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, RTP, NC 27711, USA.
Neuroscience. 2001;103(3):739-61. doi: 10.1016/s0306-4522(01)00011-2.
The present studies were undertaken to characterize the regional and temporal patterns of neurotrophin messenger RNA and protein levels for beta-nerve growth factor, brain-derived neurotrophic factor and neurotrophin-3 in the developing CNS. We have examined the levels of these neurotrophin messenger RNAs with ribonuclease protection assays and corresponding protein levels with enzyme-linked immunosorbent assays in the developing Long-Evans rat hippocampus, neocortex and cerebellum on postnatal days 1, 7, 14, 21, and 92. In addition, immunohistochemistry was used to localize the neurotrophins in these developing brain regions. Results indicated that in neocortex and hippocampus, messenger RNA for both nerve growth factor and brain-derived neurotrophic factor increased in an age-dependent manner, reaching a plateau by postnatal day 14. In the neocortex, nerve growth factor and brain-derived neurotrophic factor protein levels both peaked at postnatal day 14. In hippocampus, nerve growth factor protein peaked at postnatal day 7 while brain-derived neurotrophic factor peaked at postnatal day 14. In cerebellum, nerve growth factor messenger RNA levels were flat, while nerve growth factor protein peaked at postnatal day 7. Brain-derived neurotrophic factor messenger RNA increased in an age-dependent manner while the pattern for its protein levels was mixed. Neurotrophin-3 messeger RNA levels increased in an age-dependent manner in hippocampus, peaked at postnatal day14 in cerebellum, and no changes occurred in neocortex. Neurotrophin-3 protein was at its peak at postnatal day 1 and thereafter decreased at other postnatal days in all three brain regions. Results of neurotrophin immunohistochemistry often paralleled and complemented enzyme-linked immunosorbent assay data, demonstrating specific cell groups containing neurotrophin proteins in these regions. Within each region, patterns with regard to messenger RNA and respective protein levels for each neurotrophin were unique. No consistent relationship between patterns of neurotrophin messenger RNAs and their cognate proteins was observed between regions. The different regional patterns for neurotrophin messengerRNA and protein levels in each brain region indicate that messenger RNA studies of neurotrophin messenger RNA must be augmented by protein determination to fully characterize spatial and temporal neurotrophin distribution.
本研究旨在描述在发育中的中枢神经系统中，β-神经生长因子、脑源性神经营养因子和神经营养素-3的神经营养因子信使核糖核酸及蛋白质水平的区域和时间模式。我们采用核糖核酸酶保护分析法检测了这些神经营养因子信使核糖核酸的水平，并在出生后第1、7、14、21和92天，用酶联免疫吸附测定法检测了发育中的Long-Evans大鼠海马体、新皮质和小脑中相应的蛋白质水平。此外，免疫组织化学被用于在这些发育中的脑区定位神经营养因子。结果表明，在新皮质和海马体中，神经生长因子和脑源性神经营养因子的信使核糖核酸均以年龄依赖的方式增加，在出生后第14天达到平台期。在新皮质中，神经生长因子和脑源性神经营养因子的蛋白质水平均在出生后第14天达到峰值。在海马体中，神经生长因子蛋白质在出生后第7天达到峰值，而脑源性神经营养因子在出生后第14天达到峰值。在小脑中，神经生长因子信使核糖核酸水平平稳，而神经生长因子蛋白质在出生后第7天达到峰值。脑源性神经营养因子信使核糖核酸以年龄依赖的方式增加，而其蛋白质水平的模式则较为复杂。神经营养素-3信使核糖核酸水平在海马体中以年龄依赖的方式增加，在小脑中于出生后第14天达到峰值，在新皮质中无变化。神经营养素-3蛋白质在出生后第1天达到峰值，此后在所有三个脑区的其他出生后天数均下降。神经营养因子免疫组织化学的结果通常与酶联免疫吸附测定数据平行且互补，表明这些区域中含有神经营养因子蛋白质的特定细胞群。在每个区域内，每种神经营养因子的信使核糖核酸和相应蛋白质水平的模式都是独特的。在不同区域之间，未观察到神经营养因子信使核糖核酸模式与其同源蛋白质之间存在一致的关系。每个脑区中神经营养因子信使核糖核酸和蛋白质水平的不同区域模式表明，必须通过蛋白质测定来补充神经营养因子信使核糖核酸的信使核糖核酸研究，以全面描述神经营养因子的时空分布。
