NGF,BDNF,NT-3和GDNF在背根节不同神经元的配布的免疫组织化学证据

THE IMMUNOHISTOCHEMICAL EVIDENCE FOR THE DISTRIBUTION OF NGF, BDNF, NT-3, GDNF IN SUBPOPULATION OF NEURONS OF DORSAL ROOT GANGLIA IN ADULT CAT

为了探讨神经生长因子、脑源性神经生长因子 ,神经营养素 -3,胶原细胞源性神经生长因子在成年猫背根节神经元不同大小细胞的分布。取 L6背根节制成 2 0μm厚冰冻切片 ,用上述四种因子抗血清进行免疫组化反应。计数每一种因子阳性大、中、小型 (小于 42μm者为小型神经元 ;42～ 5 7μm者为中型神经元 ;大于 5 7μm者为大型神经元 )神经元的百分数。结果证明 ,此四种因子在背根节大、中、小神经元的阳性百分数分别为 :1.2± 0 .7,2 .1± 0 .9,3.3± 1.1;1.7± 0 .4,11.2± 1.2 ,30 .0± 1.5 ;2 6 .7± 2 .2 ,6 .2± 1.2 ,13.2± 2 .9;2 7.4± 3.3,8.1± 1.7,2 0 .1± 2 .4。表明 :在成年猫 L6背根节仅存在少数神经生长因子阳性细胞 ,而脑源性神经生长因子则主要配布于中、小神经元 ,神经营养素 -3和胶质细胞源性生长因子的免疫阳性细胞主要是大神经元 ,但也包括一些中小神经元。提示此四种因子在成年猫背根节的生理功能可能与神经元的不同大小有关。

It is well known that there are no nerve growth factor (NGF)-like immunoreactive (NGF-IR) neurons in dorsal root ganglia(DRG) of adult rat. Comparatively, the neurons for brain derived neurotrophic factor immunoreactivity (BDNF-IR) and neurotrophin-3 immunoreactivity (NT-3-IR) were located in small dark cells (B-cells) and large light cells (A-cells) respectively. However, the distribution for these neurotrophins in DRG of adult cats is not completely clear. In this study, we investigated the distribution of NGF, BDNF, NT-3 and GDNF in subpopulation of neurons from SG in adult cats. The L 6 DRG were made into 20 μm thickness frozen sections. The sections were stained using antiserum of NGF, BDNF, NT-3 and GDNF by immunohistochemistry ABC method. The percentage of positive large, medium, small neurons for NGF, BDNF, NT-3 and GDNF were counted respectively. The results were as following: The percentage of positive large, medium, small neurons for NGF, BDNF, NT-3 and GDNF were respectively: 1.2±0.7, 2.1±0.9, 3.3±1.1; 1.7±0.4, 11.2±1.2, 30.0±1.5; 26.7±2.2, 6.2±1.2, 13.2±2.9; 27.4±3.3, 8.1±1.7, 20.1±2.4. This showed that there were a few NGF positive neurons in DRG of cat and that of BDNF-IR was mainly distributed in small and medium size neurons, while positive immunoreactive products for NT-3 and GDNF were mainly distributed in large neurons besides small and medium ones. These indicate that the distribution of NGF, BDNF, NT-3 and GDNF has a little difference in subpopulation of neurons of DRG of adult cat. In addition, our results also suggeste that the distribution for four neutrophins in DRG of cat was not completely consistent with that of being reported in adult rat. Our results provide important immunohistochemical evidences for the distribution characteristics of NGF, BDNF, NT-3 and GDNF in subpopulation of neurons in DRG of adult cat.