孤啡肽及其前体mRNA在神经痛大鼠脊髓背角神经元中表达的变化

孤啡肽是新近发现的一种17肽,为阿片受体家族中一个新成员"孤儿受体"的内源性配基.孤啡肽在痛觉调制中的作用与内阿片肽明显不同,其在脊髓水平痛觉调制过程中起着重要作用.神经痛是临床上常见的一种慢性痛.本实验目的是探讨慢性限制性损伤大鼠模型上(CCI)孤啡肽及其前体mRNA在神经痛大鼠脊髓背角表达的变化.大鼠左侧后肢坐骨神经结扎,右侧假手术,通过光热刺激大鼠后肢脚掌测量抬脚潜伏期(PWL),CCI模型3天后手术侧PWL明显低于对侧,提示痛敏的出现,痛敏持续不超过30天.

PAG内微量注射OFQ并同时电针对脊髓背角单胺类和氨基酸类递质释放的影响

我们以往的工作表明,大鼠中脑导水管周围灰质(PAG)内微量注射孤啡肽(OFQ)对抗针刺镇痛;并使脊髓背角谷氨酸(Glu)释放增加,ν-氨基丁酸(GABA)、5羟色胺(5-HT)、去甲肾上腺素(NE)释放减少;脊髓背角广动力范围(WDR)神经元的C-纤维反应和后放电增多.本研究的目的是采用核团内注射、微透析加高效液相电化学检测的方法,观察PAG内微量注射OFQ并同时电针,对大鼠脊髓背角单胺类和氨基酸类递质释放的影响.

Acupuncture has been used to treat neuropathic pain for a long time, but its mechanisms of action remain unknown. In this study, we observed the effects of electroacupuncture and manual acu-puncture on neuropathic pain and on ephrin-B/EphB signaling in rats models of chronic constriction injury-induced neuropathic pain. The results showed that manual acupuncture and elec-puncture significantly reduced mechanical hypersensitivity fol owing chronic constriction injury, es-pecial y electroacupuncture treatment. Real-time PCR results revealed that ephrin-B1/B3 and EphB1/B2 mRNA expression levels were significantly increased in the spinal dorsal horns of chronic constriction injury rats. Electroacupuncture and manual acupuncture suppressed the high sion of ephrin-B1 mRNA, and elevated EphB3/B4 mRNA expression. Electroacupuncture signifi-cantly enhanced the mRNA expression of ephrin-B3 and EphB3/B6 in the dorsal horns of neuro-pathic pain rats. Western blot results revealed that electroacupuncture in particular, and manual acupuncture, significantly up-regulated ephrin-B3 protein levels in rat spinal dorsal horns. The re-sults of this study suggest that acupuncture could activate ephrin-B/EphB signaling in neuropathic pain rats and improve neurological function.

晚期周围神经损伤后感觉功能恢复中:脊髓后角P物质及降钙素基因相关肽的变化

背景:晚期周围神经损伤有无修复价值?如果脊髓神经元中P物质和降钙素基因相关肽的变化发生了不可逆的变化,其修复后也预示着感觉功能的缺失. 目的:定量研究周围神经损伤24周后,脊髓后角中P物质和降钙素基因相关肽的变化.设计:建立以大鼠坐骨神经损伤为研究对象的实验模型,损伤后24周为远期观察点,自身对照(对侧空白组),定量化研究.单位:第四军医大学骨科研究所.材料:实验于2002-10/2003-05在第四军医大学骨科研究所完成.SD大鼠55只,分成11组,即坐骨神经切断1,2,3,4,6,8,10,12,16,20,24周各组.干预:切断大鼠一侧坐骨神经并结扎其近端的方法建立周围神经损伤模型;另一侧为对照侧.应用计算机图像分析技术测试P物质和降钙素基因相关肽免疫反应区的面积.主要观察指标:各组大鼠脊髓后角中P物质和降钙素基因相关肽阳性纤维的终末分布面积的变化.结果:55只大鼠均进入结果分析.①P物质时间序列表示:周围神经损伤后2～6周,P物质在脊髓后角免疫反应区面积下降至低,随之回升,至16周恢复正常,20,24周无明显的进一步变化.②脊髓后角降钙素基因相关肽阳性纤维和终末分布面积损伤与自身对照侧的比值:1周时1.14,6周时1.13,24周时0.29,各时间点基本相似(P＞0.05)结论:周围神经损伤至晚期,脊髓后角及后根神经节细胞合成和分泌P物质及降钙素基因相关肽的功能尚未受到破坏,脊髓后角已处于一种稳定的平衡状态,仍有恢复感觉功能的神经学基础.

Effect of Electroacupuncture on Chronic Visceral Pain and Involvement of Spinal NMDA Receptor in IBS Rats

Objective:To clarify effect of electroacupuncture (EA) on relieving chronic visceral pain and the underlying neurobiological mechanism for such an effect,we observed the effect of EA on the Irritable bowel syndrome (IBS) rat and then examined spinal expression of N-methyl-D-aspartate (NMDA)receptor-1 in rats.Methods:Daily mechanical colon distention was performed on male Sprague-Dawley neonatal rats to produce IBS model.EA was applied at acupoints of Zusanli (ST 36) and Shangjuxu (ST 37)in each hind leg.Abdominal withdrawal reflex (AWR) assessment or rectus abdominis electromyograms (AEMG) recordings were then performed after EA treatment.The mRNA expression of the NMDA subtype of glutamate receptors in the spinal dorsal horn (L4-5) before and after EA was investigated by RT-PCR analysis in IBS rats.Results:The results demonstrated that EA could significantly decreased both AWR scores from behavioral test and AEMG discharges from electrophysiological recording in IBS model rats elicited by colorectal distension (CRD) stimuli with strengths of 20,40,60 and 80 mmHg,respectively (P＜0.05).Meanwhile there was a significant decrease in mRNA expression of NMDA receptor-1 in the spinal dorsal horn of IBS rats treated by EA (P＜0.05),but no such effect was observed in IBS rats treated by sham EA (inserting needles without electrical stimulation).Conclusion:These results indicate that EA can relieve chronic visceral hyperalgesia in IBS rats and this effect might be correlated with the down-regulation of NMDA receptor-1 in the dorsal hom of the spinal cord.

AIM: The aim of this study was to explore the expression of nerve growth factor(NGF) in spinal dorsal horn following crushed spinal cord injury. METHODS: The adult Srague-Dawley rat model of crushed spinal cord injury was established by the method in our laboratory, and intact spinal cord was used as control. The rats were sacrificed respectively after 24 hours, 7 days, and 21 days of operation, and the L3 spinal segments were removed out and fixed in 4% polyformaldehyde. The segments were sectioned into sections of 20 μm in thickness. The sections were stained with anti-NGF antibody by ABC method of immunohistochemistry technique. The immunoreactive intensity of NGF and the number of positive neurons as well as glial cells in dorsal horn were observed and counted under light microscope. RESULTS: The number of positive cells and immunoreactive intensity of NGF increased gradually in the dorsal horn at 24 hours, 7 days and 21 days following crushed spinal cord injury compared with control group (P＜0.01). CONCLUSION: These results indicated that NGF plays an important role in the postoperative reaction during the early period of the crushed spinal cord injury.