NGF及NGF mRNA在去部分背根猫脊髓和背根节表达的变化

THE CHANGES OF NERVE GROWTH FACTOR (NGF) AND NGF mRNA EXPRESSION IN SPINAL CORD AND DORSAL ROOT GANGLION OF PARTIAL RHIZOTOMY CATS

用成年猫单侧备用根模型 (切断一侧 L1～ 5 、L7～ S2 节段脊髓背根 ,保留 L6 背根 ) ,用免疫组织化学和原位杂交技术 ,对脊髓背角 板层、背核和 L6 背根节中神经生长因子的表达进行了动态观察。结果证明 ,部分背根去传入后 :(1)脊髓各节段双侧背角 板层的神经生长因子和神经生长因子 m RNA阳性神经元的数量及体积显著增高、增大 ;(2 )手术侧背核神经生长因子和神经生长因子 m RNA阳性神经元的增高强于非手术侧 ,但术后两时间组的手术侧之间无差异 ;(3 )备用根背根节新出现了神经生长因子 m RNA阳性神经元 ,且神经生长因子阳性神经元数量明显高于正常组 ,且随术后时间增加而递增。以上结果表明 :部分背根去传入猫脊髓背角 板层及背核内神经生长因子水平提高 ,尤其备用根背根节神经元神经生长因子的增加 ,为备用背根传入纤维侧支生芽和突触重建提供了良好的条件 。

On the basis of building cat spared dorsal root preparation (i.e.rhyzotomy of unilateral L 1～5 ,L 7～S 2 dorsal roots, leaving L 6 as a spared dorsal root), we used ABC immunohistochemistry and in situ hybridization techniques to observe the dynamic changes of NGF and NGF mRNA in spinal lamina Ⅱ, Clarke's nucleus and DRG. The results were as follows: (1) The population of NGF and NGF mRNA positive neurons and the size of NGF positive neurons in each segements of lamina Ⅱ of both sides was increased significantly after partial dorsal rhyzotomy. (2) The number of NGF and NGF mRNA positive neurons in Clarke's nucleus on operated side of both groups was higher than that on unoperated side, but was no different between operated sides of two time groups. (3) In DRG of the normal cats there showed very little NGF positive neurons and there was no NGF mRNA positive neurons, but in spared DRG of both time groups of operated sides much more NGF and NGF mRNA positive neurons gradually appeared.Our results indicate that the increase of NGF neurons in spinal lamina Ⅱ, Clarke's nucleus especially in spared DRG creates a good internal and external environments for spared root's collateral sprouting and establish synaptic connection. It helps us to explain the internal mechanism of spinal plasticity.