长期喉返神经损伤后疑核运动神经元睫状神经营养因子的表达

目的：研究长期喉返神损伤后疑核运动神经元睫状神经营养因子（ＣＮＴＦ）的表达及分布。方法：以犬单侧喉返神经损伤为实验模型，采用原位杂交及免疫组织化学技术，结合图像分析技术测定疑核ＣＭＴＦｍＲＮＡ及其蛋白表达呈阳性反应的神经元胞体灰度、体积及数量。结果：疑核运动神经元能自分泌ＣＮＴＦ，神经损伤３周内神经元ＣＮＴＦ基因表达强度及反应的胞体数明显下降，而ＣＮＴＦ蛋白表达增强，但表达的胞体数无改变。４周后基

Expression of ciliary neurotrophic factor in ambiguous nucleus motoneuron after long-term laryngeal denervation

Objective:Ciliary neurotrophic factor (CNTF) plays important roles in the maintenance and survival of motor neurons. This study attempted to explore the expression and distribution of CNTF mRNA and its protein in the ambiguous nucleus(Amb) motoneuron in order to clarify its functional state after long term laryngeal denervation. Methods: The recurrent laryngeal nerves were obtained from dogs. Brain stems were removed and sectioned for histochemistry, immunohistochemistry and in situ hybridization of CNTF. Amb motoneurons were identified by Nissl staining. The count and intensity of positive reactive motoneurons were measured by computer image processing system. Results: Transection of the laryngeal nerve led to a very marked reduction in the count and intensity of CNTF mRNA positive reactive motoneurons, and reached minimal levels at week 3. CNTF immunoreactivity increased rapidly and reached maximal levels also at week 3. At week 4, a significant increase in CNTF mRNA expression and decrease in CNTF immunoreactivity were observed. At week 6, both CNTF mRNA and its protein expression were significantly less than those of unlesioned contraletaral sides. Although a difference between week 6 and 12 was observed, the motoneurons were generally stable in the expression level of CNTF mRNA and its protein, and in the size and count after 12 weeks, with 78%, 84.4%, 80.9% and 83.7% respectively as compared with the unlesioned contralateral Amb. Conclusion: The results indicate that although degenerating changes occurre in the Amb motoneurons after long term laryngeal denervation, the ciliary neurotrophic factors activity of the lesioned motoneurons is still maintained at a certain level. [