鞘内注射舒芬太尼和PKC抑制剂对神经病理痛大鼠痛阈及脊髓背角N-甲基-D-天冬氨受体和降钙素基因相关肽表达的影响

Effect of intrathecal sufentanil and protein kinase C inhibitor on pain threshold and the expression of NMDA receptor/CGRP in spinal dorsal horn in rats with neuropathic pain

目的:观察鞘内注射舒芬太尼和PKC抑制剂对神经病理痛大鼠痛阈及脊髓背角N-甲基-D-天冬氨受体(N-methyl-D-aspartate receptor,NMDAR)、降钙素基因相关肽(calcitonin gene-related peptide,CGRP)表达的影响。方法:将54只健康雄性SD大鼠随机分为6组(n=9):舒芬太尼组[S+保留神经损伤(spared nerve injury model,SNI)组]、舒芬太尼+PKC抑制剂组(SP+SNI组)和PKC抑制剂组(P+SNI组)在SNI模型制作后14 d内每天分别鞘内注射舒芬太尼1μg、舒芬太尼1μg+PKC抑制剂11μg、PKC抑制剂11μg,注射药物容量均为20μL。对照组(C组)、假手术组(S组)和神经病理痛模型组(SNI组)则在上述相同时间点分别注入0.9%的生理盐水20μL。在模型制作前1 d和模型制作后14 d内,对各组大鼠进行疼痛行为学观察,并用免疫组织化学法观察各组大鼠L5节段水平脊髓背角NMDAR和CGRP的表达。结果:与C组和S组比较,SNI组在SNI术后均出现机械刺激痛阈降低(P<0.01),且脊髓背角NMDAR和CGRP免疫阳性产物数量和表达增加(P<0.01)。与SNI组比较,S+SNI组、P+SNI组和SP+SNI组注药后机械刺激痛阈提高(P<0.01),脊髓背角NMDAR和CGRP免疫阳性产物表达降低(P<0.05或0.01),且3组比较差异有统计学意义(P<0.05)。结论:鞘内注射舒芬太尼和PKC抑制剂对神经病理痛大鼠具有明显的抗伤害效应,同时可显著抑制大鼠脊髓背角NMDAR和CGRP表达。

Objective： To investigate the effect of intrathecal sufentanil and protein kinase C inhibitor on pain threshold and the expression of N-methyl-D-aspartate receaptors（NMDAR）/calcitonin gene-related peptide（CGRP） in spinal dorsal horn in rats with neuropathic pain. Methods： Fifty-four healthy male Sprague-Dawley rats were randomly divided into 6 groups（9 in each group）.The rats in the sham group（Group S） ＋ spared nerve injury（SNI）,SP＋SNI,and P＋SNI were intrathecally injected sufentanil（1 μg）,sufentanil（1 μg） and chelerythrine chloride（11 μg）,chelerythrine chloride（11 μg） followed by 10 μL normal saline once every day for 14 days post-operatively,respectively.Similarly,rats in the control group（Group C）,the sham group（Group S）,and SNI model group（Group SNI） were intrathecally injected 20 μL normal saline in the uniform interval.Pain behaviours were measured on Day 1 pre-surgery and on Day 1,2,7,and 14 after the intrathecal injection.The expressions of NMDAR and CGRP in the spinal dorsal horn of L5 segment were determined by immunohistochemistry on Day 2,7,and 14 after the intrathecal injection. Results： Compared with Group C and Group S,mechanical allodynia threshold in group SNI was decreased after the surgery（P〈0.01）,and expressions of NMDAR and CGRP immunoreactive soma in the spinal dorsal horn was significantly increased（P〈0.01）.Mechanical stimulation pain threshold was elevated in Group S＋SNI,Group P＋SNI,and Group SP＋SNI compared with Group SNI（P〈0.01）,while expressions of NMDAR and CGRP immunoreactive soma in Group S＋SNI,Group P ＋SNI,and Group SP＋SNI were significantly decreased（P〈0.05 or 0.01）. Conclusion： Intrathecal administration of sulfentanil and protein kinase C inhibitor can provide significant antinociception in rats with neuropathic pain and obviously inhibit the upregulation of NMDAR and CGRP expressions in the spinal dorsal horn of SNI rat models.