治疗浓度和剂量胶原酶对大鼠脊神经背根神经节安全性的病理研究

Pathological evaluation of the toxicity of collagenase at the therapeutic concentration and dosage on rat dorsal root ganglion

目的从病理学角度阐述胶原酶化学髓核溶解术中治疗浓度和剂量胶原酶对大鼠脊神经背根神经节的安全性。方法对57只Sprague-Dawley雄性大鼠按随机配伍原则进行分组，分别为正常对照组（n=9）；胶原酶手术急性损伤组（n=91、亚急性损伤组（n=10）和慢性损伤组（n=7）；生理盐水手术急性损伤组（n=7）、亚急性损伤组（n=8）和慢性损伤组m=7）。手术暴露大鼠左侧腰5背根神经节，分别在胶原酶手术各组局部滴注胶原酶1mL（1200U／4mL），生理盐水手术各组局部滴注生理盐水1mL。分别于注药后1h、7d、30d取包含背根神经节的一段神经做病理光镜和透射电子显微镜检测，比较各组的病理改变。结果光镜下各组背根神经节的细胞数、胞膜、胞浆、胞核形态和细胞间神经纤维、血管均无明显变化和差别。透射电镜下各组背根神经节的细胞数、细胞大体形态、胞膜和节内神经纤维亦无明显变化和差别，但胶原酶手术各组背根神经节细胞胞内细胞器超微结构与正常对照组和相应生理盐水手术各组比较有差别，表现为核仁部分偏向一侧，大量线粒体肿胀，部分嵴断裂和空泡形成。病理光镜和透射电镜均未见节细胞成群细胞坏死、细胞膜早期破裂和凋亡小体形成。结论胶原酶化学髓核溶解术中治疗浓度和剂量胶原酶对大鼠脊神经背根神经节细胞有一定的损伤，应慎重选择胶原酶的用药剂量和浓度，提高胶原酶临床应用的安全性。

Objective To examine the pathological changes of rat dorsal root ganglion （DRG） exposed to collagenase at the therapeutic concentration and dosage and evaluate the safety of collagenase for application in chemonucleolysis. Methods Fifty-seven male SD rats were randomly assigned into 7 groups, including a normal control group （n=9）, 3 coUagenase damage （acute, cubacute and chronic） groups （n=9, 10, and 7, respectively）, and 3 saline damage （acute, cubacute and chronic） groups （n=7, 8, and 7, respectively）. The left fifth lumbar DRG of the rats was surgically exposed and 1 mL collagenase solution （300 U） or isotonic saline was carefully applied. The morphology of the DRG was observed under light microscope and electron microscope 1 h, 1 week and 1 month after the operation. Results No obvious pathological changes were found in the nerve fibers, blood vessels and the morphology of the neurons in the DRG after application ofcollagenase or saline. But compared with the normal control and the saline groups, some ultrastructural changes occurred in the neurons in the DRG after collagenase application, manifested by lateral shift of the nucleolus, mitochondrial swelling, loss of mitochondria crest, mitochondrial vacuolization, swelling of the endoplasmic reticulum, and wrinkled nuclear membrane. No necrosis or apoptosis was observed in the neurons under light or electron microscope. Conclusion Collagenase at the therapeutic concentration and dosage for chemonucleolysis does cause some damages in rat DRG, suggesting the necessity of more prudent choice of the concentration and dosage ofcollagenase in clinical application.