大鼠坐骨神经损伤后神经纤维的再生规律与神经功能恢复的关系(英文)

Relationship between the regeneration rules of nerve fiber and the rehabilitation of nerve functions after the sciatic nerve injury in rats

背景:计算机三维图像重建技术能实现对神经组织的立体化观察研究,在阐明神经组织显微和超微结构、结构之间毗邻关系、结构与功能之间的联系以及显示某些成分的空间分布等方面具有其他方法不可比拟的优势。目的:利用大鼠坐骨神经损伤后再生神经组织连续切片重建其显微及超微结构的三维立体图像,阐明显微及超微结构的三维形态特点及变化规律。设计:随机对照实验研究。地点和对象:实验地点:解放军第三军医大学第三附属医院实验动物中心,实验对象:雌性成年Wistar大鼠90只,体质量225～250g。干预:建立大鼠坐骨神经切割伤模型,并用硅胶管桥接坐骨神经长6mm缺损。在连续光镜图像和电镜图像基础上运用直接体素绘制法重建并显示了坐骨神经损伤后变性、再生过程中神经纤维组织显微及超微结构的三维立体形态。主要观察指标:大鼠坐骨神经损伤后显微及超微结构的形态特点。结果:重建的三维结构可通过任意旋转和移动进行多角度立体观察,显示新生神经纤维与正常神经纤维在立体构象上的差异:如伤后15d可见大量雪旺细胞增生并向远端延伸,形成Bürger's带;伤后2个月中段再生神经电镜三维图像显示轴索陷入雪旺细胞胞浆内并开始形成髓鞘,轴索内微管、微丝增生,雪旺细胞胞浆内可见丰富的线粒体;

BACKGROUND:Three-dimensional(3-D) computerized image reconstruction techniqu e can realize the three-dimensional observation on nerve tissue,which has unexa mpled advantages in illustrating the microstructure and ultrastructure of nerve tissue, the spacial adjacent relationship between different structures,the relat ion between structure and function,and displaying the dimensional distribution o f some structures,etc. OBJECTIVE:To reconstruct the 3-D images of microstructure and ultrastructure of regenerated sciatic nerve through serial sectioning after sciatic nerve injur y in rats for elucidation the 3-D morphological characteristics and the transfo rmation rule of microstructure and ultrastructure. DESIGN: A randomized controlled study. SETTINGS and PARTICIPANTS:The study was conducted at the experimental animal c enter of the Third Affiliated Hospital of Third Military Medical University of C hinese PLA. A total of 90 female adult Wistar rats with a body mass from 225 g t o 250 g were selected. INTERVENTIONS:The sciatic nerve incision injury model was established.The 6 mm defect of the sciatic nerve was bridge-connected with silicone tube.A 3-D mor phology of microstructure and ultrastructure of the nerve fiber during the degen eration and regeneration process after sciatic nerve injury was displayed by dir ect volume rendering(DVR) method on the basis of serial images under optical mic roscope and electron microscope. MAIN OUTCOME MEASURES:The 3-D morphological characteristics of microstructure and ultrastructure of the sciatic nerve after injury. RESULTS:The reconstructed 3-D microstructure and ultrastructure of the sciati c nerve could be observed from multiple angles by random rotations and displacem ents to reveal the differences of 3-D structure between newborn nerve fibers an d normal nerve fibers,for example,at 15 days after injury, a lot of Schwann's Ce lls(SC) could be seen and extended towards distal end to form Burger's zone;At 2 months after injury, as revealed by 3-D image of electron microscope, neurite of the regenerated nerve got into SC plasma to form myelin,the microtubule and m icrofilament in neurite proliferated, and plenty of mitochondria could be seen i n SC plasma;and at 3 months after injury,myelination could be seen in newborn ne rve and the formation of node of Ranvier could seldom be seen. CONCLUSION:The results of reconstruction can directly display the morphologica l differences between regenerated and normal sciatic nerve fiber in rats,which t herefore can be used as a new method in the study of 3-D observation of sciatic nerve injury.