不同程度损伤对动眼神经功能修复的影响

Effect of Different Degrees of Injury on Functional Reparation of Oculomotor Nerve

目的研究不同程度损伤对鼠动眼神经功能修复的影响与机制。方法成年SD大鼠35只,随机分为3组:正常对照组(n=5)动眼神经不损伤;切断吻合组(n=15)在海绵窦内锐性切断右侧动眼神经主干后立即用11-0无创缝线行端端对位缝合;压榨损伤组(n=15)用显微持针器完全夹闭海绵窦段动眼神经主干,持续5 s。术后观察动眼神经功能并进行神经组织学和解剖学研究。结果不同损伤均可导致神经元的数量减少,分布散乱,亚核分布结构改变,神经纤维和髓鞘的结构破坏,轴突芽生及再生纤维分布的特异性降低,而且上述改变在神经切断组更加明显。观察期中瞳孔括约肌及眼外肌的功能恢复速度与最终的恢复水平,神经压榨组都明显优于神经切断组。结论动眼神经轻度损伤较重度损伤功能恢复更好,这与幸存神经元数量较多,结构容易修复,神经元和再生纤维对眼外肌支配的特异性较高有关。

Objective To study the influence and mechanism of different injury on functional reparation of oculomotor nerve in adult Sprague-Dawley （SD） rats. Methods Thirty-five adult SD rats were divided into three groups randomly. In section-suture group, the oculomotor nerves were sectioned at cavernous sinus and end-to-end sutures were conducted immediately in 15 rats. In clip-injury group, the oculomotor nerves were only clipped with needleholder for 5 s in another 15 rats, and 5 rats without injury were kept as normal control group. The function of oculomotor nerve was observed periodically, and neuroanatomical and histological aspects were observed with light micro- scope and electron microscope. Results In both groups after injury, several changes on oculomotor nerve occurred including number reduction of neurons, dispersion in distribution, disappearance of sub-nuclear structure, structure destruction of fibers and myelin sheath, neurite gemmation, and specificity decrease in fibers distribution, while all these changes in section-suture group were more obvious. The reparation velocity and the possible level of functional recovery of pupillae sphincter muscle were better than those of extraocular muscles. Conclusion Better function reparation could be expected in clip-injury group with minor survival neurons, easier reparation in structure, and higher traocular muscles.