SD大鼠动眼神经不同部位损伤后对靶器官特异性支配的实验研究

目的研究不同部位损伤对Sprague-Dawley（SD）大鼠动眼神经功能修复的影响及可能机制。方法实验Ⅰ组大鼠（n=24）经幕下、实验Ⅱ组（n=24）大鼠经眶上裂干预动眼神经，术后通过前庭眼反射评估眼外肌在垂直、水平方向的恢复程度。经右侧上直肌注射辣根过氧化酶（HRP），逆行追踪中脑动眼神经核团内神经元分布；48h后行动眼神经组织学、解剖学研究。结果实验Ⅰ组大鼠支配上直肌的神经纤维有45％～51％由对侧中脑运动神经元发出：实验Ⅱ组81％～87％由对侧中脑运动神经元发出，神经元在中脑的分布更接近正常大鼠。实验Ⅱ组大鼠眼外肌功能恢复程度明显优于实验Ⅰ组大鼠。结论动眼神经损伤部位距离眼外肌越近，最终的神经功能恢复水平越好，这可能与再生神经纤维通过损伤部位时的迷行程度相关。

Specific target organ innervating of the oculomotor nerve with different site injuries in SD rats: experiment study

Objective To investigate the effect of different site injury to the oculomotor nerve on functional recovery and its probable mechanism in SD rats. Methods The third cranial nerve was dissected and repaired at the subtentorial area （group Ⅰ, n = 24） and the supraorbital fissure （group Ⅱ, n = 24）, the functional recovery was evaluated by measuring the horizontal and vertical vestibule-ocular reflexes. HRP was injected to the superior rectus muscle to retrogradely label the neuron distribution in the oculomotor nucleus. The anatomy and histology of the oculomotor nerve were studied 48 h after the injection. Results 45-51% of the nerve fibers innervating the superior rectus muscle in rats of group Ⅰ and 81-87% in group Ⅱ came from the neuron in contralateral midbrain, and the distribution of the neurons in midbrain was closer to normal rats in group Ⅱ than group Ⅰ. The degree of functional recovery of extraocular muscle was also significantly better in group Ⅱ than group Ⅰ. Conclusion The closer the injury site is to the target organ, the better the functional recovery, which may be related to the aberrant degree of the regenerated nerve fibers running in the injury fragment of the nerve.