硬膜外腔植入髓核对大鼠脊髓背根神经节SP和CGRP表达的影响

摘要

目的:观察硬膜外腔植入异体髓核对大鼠L6-S1脊髓背根神经节细胞SP和CGRP表达的影响,以期为椎间盘源性疼痛发病机制提供细胞生物学基础.方法:雄性SD大鼠(体重260～280g)随机分为四组:脂肪+生理盐水组(FS组)、脂肪+胶原酶组(FE组)、髓核+生理盐水组(NS组)、髓核+胶原酶组(NE组),每组n=6.观察指标:(1)痛阈测定:在手术前、术后第7天及术后第15天分别测定鼠尾对伤害性机械刺激的反应.(2)SP和CGRP表达:术后第15天取L6-S1背根神经节,采用免疫组织化学染色方法观察髓核对背根神经节细胞肽类神经递质SP和CGRP表达的影响.结果:(1)痛阈变化:NS组在术后第7天和第15天对机械刺激表现为痛觉过敏(P＜0.05),而其他组大鼠术后痛阈与术前相比没有显著差异(P＞0.05)；术后第7天和第15天NS组与其他组组间比较痛阈显著性降低(P＜0.05).(2)SP和CGRP表达:术后15天FE组大鼠与FS组相比,背根神经节细胞SP和CGRP表达没有显著性差异(P＞ 0.05); NS组与FS组相比背根神经节细胞SP和CGRP表达显著增加(P＜ 0.05)；NE组与NS组相比背根神经节细胞SP和CGRP表达显著降低(P＜0.05),接近于FS组水平(P＞0.05).结论:硬膜外腔植入异体髓核可引起背根神经节细胞SP和CGRP表达增加,这可能是导致大鼠出现痛觉超敏原因之一.%Objective: To observe the effect of nucleus pulposus allografted into the epidural space on the expressions of SP and CGRP in rat's DRG neurons, so as to provide theoretical evidence for discogenic pain. Methods: Male Sprague-Dawley rats were randomly divided into four groups with 6 rats in each: fat + normal saline group (FS group), fat + collagenase group (FE group), nucleus pulposus + normal saline group (NS group), and nucleus pulposus + collagenase group (NE group). The allografted fat and nucleus pulposus were provided by the other 8 male SD rats. (1) Before surgery and at 7th and 15th day after surgery, the responses of tail to mechanical stimulation were observed. (2) 15th day after surgery, the L6-S1 DRGs were seperated, and the expressions of SP and CGRP in DRGs were detected by using immunohistochemistry method. Results: (1) The postoperative threshold values to mechanical stimulation in the NS group were significantly decreased when compared with the preoperative ones (P < 0.05 ), while other groups was not significantly changed (P > 0.05); At 7th and 15th day after surgery, the threshold in the NS group were significantly lower than in other groups (P < 0.05). (2) At 15th day after surgery, the expressions of SP and CGRP in DRGs in NS group was stronger than those in FS group (P < 0. 05); but the expressions of SP and CGRP in NE goup was less than those in NS without signifi cant difference compared with FS group (P> 0.05). Conclusion: Nucleus pulposus allografted into the epidural space can increase the SP and CGRP expressions in DRG, which may lead to allodynia.