兔腰神经根慢性压迫和炎症刺激后背根神经节的形态学变化研究

目的 分别经光镜和电镜观察兔腰神经根经慢性压迫和炎症刺激后背根神经节(dorsalrootganglion，DRG)的形态学变化。方法 纯种新西兰大白兔20只，随机分为对照组(5只)和实验组(15只)，实验组又分为损伤后10d、30d和90d组。取兔尾部的自体髓核组织放入内径1．5mm、外径2．5mm、管壁带孔的硅胶管内，压迫左侧L，神经根，实验组各亚组分别于造模后10d、30d、90d取材，作光镜及电镜观察。结果 10d组中，经压迫和炎症刺激后神经根与DRG胞膜水肿，内膜间隙明显充血、水肿，大量炎性细胞浸润，出现变性、坏死及小胶质细胞“嗜神经”现象；DRG胞质内粗面内质网及线粒体等细胞器含量减少，粗面内质网核糖体脱落，线粒体肿胀；细胞核常染色质淡染且分布不均匀，核膜皱褶。30d组DRG胞膜稍增厚，节细胞染色不均，部分神经元出现变性、坏死，DRG溶酶体与滑面内质网含量增多，线粒体肿胀，嵴部分消失，核仁浓缩偏向一侧。90d组DRG胞膜明显增厚，节细胞内纤维样改变：溶酶体及滑面内质网含量增多，线粒体肿胀、嵴消失，核仁浓缩居中。结论 神经根慢性压迫和自体髓核刺激可导致神经组织出现水肿、炎性细胞浸润以及神经纤维增生等神经变性改变。

The morphologic changes of dorsal root ganglion after lumbar nerve root being under chronic compression and inflammatory stimulation in rabbits

Objective To observe the morphologic changes of dorsal root ganglion in the lumbar region of rabbits after the nerve root was under chronic compression and inflammatory stimulation. Methods Twenty New Zealand rabbits were recruited for this study, of which 5 served as the control (control group), and the rest were randomized into 3 experimental subgroups: 10d group, 30d group, 90d group, respectively. The autologous nucleus pulposus from the tails (about 5mg) was put into the silastic tube (inner meter of 1.5mm, external diameter 2.5mm and length 12mm), which was inserted into the left L 7 intervertebral foramen to compress the lumbar nerve root. Sham operation was performed with the rabbits in the control group. The nerve root and the dorsal root ganglia were harvested and processed and observed with light microscope and electron microscope after 10d, 30d, 90d, respectively. Results In the 10d group, obvious hyperemia, edema and infiltration of inflammatory cells in the interspace of the intima of the dorsal root ganglia (DRG) could be observed. Pyknosis, degeneration and necrosis were also found in some of the nerve cells. Electron microscopic observation showed that the number of the rough endoplasmic reticulum and mitochondrion decreased, ribosome exfoliated, mitochondrion swelled. In 30d group, typical degeneration and necrosis became more obvious. Electron microscope showed that the number of lysosome and smooth endoplasmic reticulum increased, mitochondrion swelled and its cristae disappeared, nuclei concentrated and deviated. In 90d group, significant proliferation of fibrocyte could be observed. At the same time, dura mater and arachnoid of spinal cord around the nerve root were notably thickened, and became fibrogenesis. Electron microscope also showed the increment of the lysosome and smooth endoplasmic reticulum, the swelling of mitochondrion, the loss of its cristae and the concentration of the nucleolus in the central part of the nuclei. No significant changes were found in the control group. Conclusion Pathological changes of neural degeneration such as edema, inflammatory infiltration could be observed in dorsal root ganglion after the nerve root was under chronic compression and stimulation by autologous nucleus pulposus.