单侧坐骨神经干髓核移植对大鼠双足痛阈的影响及其可能机制的探讨

Effect of nucleus pulposus allografted into sciatic nerve on pain threshold in rats

目的观测髓核组织对单侧坐骨神经干的损伤作用,探讨这种损伤作用与大鼠双足痛阈之间的关系。方法24只雄性SD大鼠（体重260-280g）随机分为四组：、假手术组、脂肪组、肌肉组、髓核组,每组n=6。另外3只雄性SD大鼠用来提供异体脂肪、肌肉和髓核,移植到各组一侧坐骨神经干,用神经行为学的方法观测大鼠双足痛阈变化,并于术后第10d、20d取植入侧坐骨神经用病理切片组织化学染色方法光镜观察坐骨神经干组织学变化。结果术后3、5、7、10、15、20、25、30、35d对照组双后肢均未出现痛觉过敏,而髓核组双侧后肢均出现明显的痛觉过敏,并且以术后7-10d最明显;组织学光镜观察发现髓核组植入侧坐骨神经干出现水肿、大量淋巴细胞浸润,部分髓鞘呈空泡样变等损伤表现,术后10d表现明显。结论髓核组织对坐骨神经干有炎性损伤作用,此损伤作用与痛觉过敏可能存在联系。

Objective To observe the effect of nucleus pulpsus allografted the sciatic nerve on pain threshold in rats,so as to provide theoretical evidence for discogenic pain.Methods The expriment was carried out in the animal experimental center of Xuanwu Hospital,Capital University of Medical Sciences.Twenty-four male Sprague-Dawley rats were randomly divided into four groups with 6 rats in each：sham-operated group,fat group,muscle group and nucleus pulpsus group.The allografted fat,muscle and nucleus pulpsus were provided by the other 3 male SD rats.Rats in the sham-operated group were given an sciatic nerve exposure without any graft implantatoin.In the fat group,muscle group and nucleus pulpsus group,rats had allografts of adipose tissue（approximately 10 mg）,muscly tissue（approximately 10 mg） and nucleus pulposus（approximately 10 mg） implanted into sciatic nerve,respectively.Preoperatively and 3,5,7,10,15,20,25,30 and 35 days postoperatively,the mechanical stimulation of both hind paws were observed.Using microscope try to find out the histological changes of sciatic nerve.Results All the 24 rats were involved in the analysis of results.The postoperative threshold values of rats to mechanical stimulation in the sham-operated group,fat group and muscle group were not significantly different from the preopertive ones（P〉0.05）.In the nucleus pulposus group,there was mechanical hyperalgesias after nucleus pulposus allografted into the sciatic nerve（P〈0.05）,especially in 7-10 day after surgery.Inflammation,edema,lymphocyte increasing and swelling are found around the sciatic nerve allografted nucleus pulposus especially in 10 days after surgery too.Conclusion Nucleus pulposus allografted into the sciatic nerve can lead to the hyperalgesia of both feet of rats,which may be one of the reasons for radicular pain of a lumbar disc herniation resulted from nucleus pulposus.