髓核对大鼠腰神经根非压迫性损伤的组织形态学研究

目的　观察硬膜外移植自体髓核后 ,大鼠神经根组织形态学的变化。方法　 2 8只Sprague Dawley(SD)雄性大鼠随机分成对照组和实验组 ,分别将自体肌肉混悬液和尾椎髓核混悬液注射到腰椎硬膜外腔 ,对神经根组织进行形态学观察。结果　在无机械压迫情况下 ,大鼠硬膜外移植自体髓核能使马尾神经根组织形态产生明显改变。结论　髓核所致的炎性反应是引起神经根损伤和坐骨神经痛的重要原因之一     

硬膜外移植自体髓核对大鼠神经根功能和组织学的影响

目的：探讨无机械压迫时，腰椎间盘髓核突出引起腰腿痛的发病机制。方法：用硬膜外穿刺的方法给大鼠注射生理盐水及自体髓核混悬液，并对机械刺激缩爪阈值、马尾神经传导速度，神经根组织形态、疼痛行为进行了测定和观察。结果：大鼠硬膜外移植自体髓核能产生明显的痛觉过敏反应，马尾神经传导速度和神经根组织形态产生明显改变。结论：髓核所致的炎症反应是引起坐骨神经痛的重要原因之一。     

硬膜外移植自体髓核对大鼠神经根功能和组织学的影响

目的:探讨无机械压迫时,腰椎间盘髓核突出引起腰腿痛的发病机制.方法:用硬膜外穿刺的方法给大鼠注射生理盐水及自体髓核混悬液,并对机械刺激缩爪阈值、马尾神经传导速度,神经根组织形态、疼痛行为进行了测定和观察.结果:大鼠硬膜外移植自体髓核能产生明显的痛觉过敏反应,马尾神经传导速度和神经根组织形态产生明显改变.结论:髓核所致的炎症反应是引起坐骨神经痛的重要原因之一.     

大鼠非压迫性髓核突出模型的建立

目的：设计一种新的非压迫性腰椎间盘髓核突出动物模型。方法：16只SD雄性大鼠随机分对照组和实验组，分别将生理盐水和大鼠自身尾椎髓核混悬液注射到腰椎硬膜外腔，对其马尾神经传导速度和神经根组织形态学进行观察。结果：无明显机械压迫情况下，大鼠硬膜外移植自体髓核能使马尾神经根传导速度和组织形态产生明显改变。结论：本动物模型简单、可靠、费用低廉，为进一步研究腰椎间盘突出症提供了一种动物模型。     

大鼠非压迫性髓核突出模型的建立

目的:设计一种新的非压迫性腰椎间盘髓核突出动物模型。方法:16只SD雄性大鼠随机分对照组和实验组,分别将生理盐水和大鼠自身尾椎髓核混悬液注射到腰椎硬膜外腔,对其马尾神经传导速度和神经根组织形态学进行观察。结果:无明显机械压迫情况下,大鼠硬膜外移植自体髓核能使马尾神经根传导速度和组织形态产生明显改变。结论:本动物模型简单、可靠、费用低廉,为进一步研究腰椎间盘突出症提供了一种动物模型。     

大鼠非压迫性髓核突出模型的建立

目的:设计一种新的非压迫性腰椎间盘髓核突出动物模型.方法:16只SD雄性大鼠随机分对照组和实验组,分别将生理盐水和大鼠自身尾椎髓核混悬液注射到腰椎硬膜外腔,对其马尾神经传导速度和神经根组织形态学进行观察.结果:无明显机械压迫情况下,大鼠硬膜外移植自体髓核能使马尾神经根传导速度和组织形态产生明显改变.结论:本动物模型简单、可靠、费用低廉,为进一步研究腰椎间盘突出症提供了一种动物模型.     

自体髓核移植后大鼠腰髓背角痛觉相关物质的变化

目的 :探讨腰椎间盘突出症相关腰腿痛发病的可能机制。方法 :在大鼠的硬膜外腔移植自体髓核 ,然后通过免疫组化的方法测定大鼠L4～ 6脊髓后角中CGRP和SP的变化。结果 :在硬膜外腔移植自体髓核后 ,L4～ 6节段脊髓背角浅层中CGRP和SP阳性神经纤维终末的面积也明显增加 ,统计学分析证实与对照组相比较有显著性差别 (P <0 .0 5 )。结论 :髓核本身的自身免疫和 /或生物化学炎症反应在腰椎间盘突出症相关的腰腿痛中起到重要的作用     

周围神经旁移植自体髓核对大鼠疼痛行为的影响

目的　探讨髓核在坐骨神经痛发病机制中的作用。方法　选择 16只SD雄性大鼠随机分为两组 ,分别将自体尾椎髓核混悬液注射到腰椎硬膜外腔或坐骨神经周围。测定其后肢机械刺激缩爪阈值。结果　在没有明显机械压迫下 ,腰椎硬膜外腔的髓核使大鼠后肢产生明显的痛觉过敏反应 ,坐骨神经旁的髓核不能使大鼠产生上述变化。结论　与髓核相关的炎症的介质是引起坐骨神经痛的原因之一 ,神经根缺乏神经外膜保护是引起疼痛的解剖学基础。     

一氧化氮在神经根性疼痛中的作用

目的：探索一氧化氮(NO)在髓核突出所致的神经根性疼痛中的作用。方法：取大鼠自体尾椎髓核无压迫下放置在L4和L5神经根表面，分别在术后3d及1、2、3、4周时观察大鼠后足机械刺激和热刺激敏感性的变化，并用免疫组化方法对移植髓核中的一氧化氮合酶(NOS)进行检测．探索NO在疼痛中的作用：结果：在无明显机械压迫情况下，大鼠腰神经根上放置自体髓核可产生痛觉过敏，移植髓核组织中NOS染色阳性一结论：髓核自身是引起腰腿痛的重要原因，NO可能参与疼痛的产生.     

白细胞介素-1α在髓核源性神经根性疼痛中的作用

目的:探讨白细胞介素-1琢(IL-1琢)是否参与髓核突出所致的坐骨神经疼痛的产生。方法:将大鼠自体尾椎的髓核无压迫下放置在L4和L5神经根表面,在术后不同时间测量大鼠后足对机械刺激敏感性的变化,同时用免疫组化方法对移植髓核中的IL-1琢进行检测。结果:在无明显机械压迫的情况下,大鼠腰神经根上放置自体髓核后,术侧后足可产生明显机械刺激痛觉过敏;实验组大鼠移植髓核组织中IL-1琢免疫组织化学染色阳性。结论:髓核组织的生物学作用是引起腰腿痛的重要因素,炎性介质IL-1琢可能参与疼痛的发生。     

米帕林对硬膜外移植自体髓核大鼠疼痛相关行为的影响

目的：探讨与椎间盘突出相关的腰腿痛的发病机制。方法：通过硬膜外置管的方法给硬膜外移植自体髓核的大鼠注射生理盐水及阿的平,并对其疼痛相关行为进行了观察。结果：大鼠硬膜外移植自体髓核后能产生明显的疼痛相关行为,注射生理盐水后疼痛相关行为无明显改善,在注射阿的平后,大鼠的疼痛相关行为明显改善,与髓核移植组比较,在术后3－9d有显著性区别。结论：磷脂酶A2在腰椎间盘相关性腰腿痛的发病机制中起重要的作用,研制有效的磷脂酶A2抑制剂能进一步提高腰腿痛的治疗。     

Effect of nucleus pulposus on the neural activity of dorsal root ganglion

STUDY DESIGN: This study was designed to investigate, using neurophysiologic techniques in an in vivo rat model, the effect of application of nucleus pulposus to the nerve root on the neural activity of the dorsal root ganglion and the corresponding receptive fields. OBJECTIVES: To assess a further role of the dorsal root ganglion in mechanisms of radicular pain in lumbar disc herniation. SUMMARY OF BACKGROUND DATA: It has been suggested that the epidural application of autologous nucleus pulposus without mechanical compression causes nerve root inflammation and related radicular pain in lumbar disc herniation. Concerning the dorsal root ganglion, its mechanical hypersensitivity and potential for generating ectopic discharges have been reported. However, the effect of autologous nucleus pulposus on the dorsal root ganglion is uncertain. METHODS: In adult Sprague-Dawley rats spontaneous neural activity was recorded from the surgically exposed L5 dorsal root using electrophysiologic techniques, and the mechanosensitivity of L5 dorsal root ganglia and corresponding receptive fields on the hind paw were measured using calibrated nylon filaments. Autologous nucleus pulposus from the tail or fat was implanted at the L5 nerve root. Neural activity was monitored for 6 hours. RESULTS: Spontaneous neural activity in the nucleus pulposus group gradually increased and showed significant differences compared with the fat group from 2.5 to 6 hours after exposure. The mechanosensitivity of the dorsal root ganglia showed significant increases compared with the fat group. CONCLUSIONS: After application of nucleus pulposus to the nerve root, the dorsal root ganglion demonstrated increased excitability and mechanical hypersensitivity. These results suggest that nucleus pulposus causes excitatory changes in the dorsal root ganglion.     

Application of nucleus pulposus to the nerve root simultaneously reduces blood flow in dorsal root ganglion and corresponding hindpaw in the rat

STUDY DESIGN: An experimental study to clarify the effects of nucleus pulposus on blood flow in the dorsal root ganglion and hindpaws. OBJECTIVES: To investigate the effects of application of nucleus pulposus to nerve root on blood flow in the dorsal root ganglion and the corresponding hindpaw. SUMMARY OF BACKGROUND DATA: It has been reported experimentally that application of nucleus pulposus into the epidural space induces morphologic and functional changes in the nerve roots and induces compartment syndrome in the dorsal root ganglia. However, it has not been clarified which of these changes induces symptoms in the lower limbs. METHODS: Sixteen adult, female Sprague-Dawley rats had the left L5 nerve root and associated dorsal root ganglions exposed. Autologous nucleus pulposus was applied to the L5 nerve root, just proximal to the dorsal root ganglion (NP group). For control, the same volume of muscle tissue was applied similarly to the neural tissue (control group). Blood flow in the dorsal root ganglion, corresponding hindpaw, and the contralateral hindpaw was continuously monitored by two-channel laser Doppler flowmeter for 3 hours. After measurement of blood flow, the nerve root and dorsal root ganglion were processed for histology and evaluated by light microscope. RESULTS: Blood flow in the NP group was reduced, not only in the dorsal root ganglion, but also in the corresponding hindpaw. These reductions were statistically significant compared with the control group (P < 0.01). Edema was the principal pathologic finding seen consistently in the nerve roots and in many of the associated dorsal root ganglia from nucleus pulposus-treated animals. CONCLUSION: Application of nucleus pulposus to nerve root decreased blood flow in the dorsal root ganglion and corresponding hindpaw. These basic pathophysiologic changes are associated with compression injuries caused by herniated discs and are accepted neuropathologic mechanisms of injury associated with painful neuropathies. These acute observations in the dorsal root ganglion and the hindpaw may be important initial factors in the pathogenesis of radicular leg pain (sciatica) due to disc herniation.     

Mechanical compression of the lumbar nerve root alters pain-related behaviors induced by the nucleus pulposus in the rat.

The purpose of this study was to refine a method of nerve-root injury in the rat to produce hyperalgesia, a pain-related behavior, and to determine if there were any relationships between the histological extent of nerve-root injury and the magnitude of hyperalgesia. Three methods were used to produce hyperalgesia: irritation of a nerve root by ectopic nucleus pulposus, silk loop alone, or both silk loop and ectopic nucleus pulposus. Autologous nucleus pulposus obtained from coccygeal intervertebral discs was relocated on the lumbar nerve roots after laminectomy. Two loops of 4-0 silk were placed around the exposed nerve roots. Hyperalgesia was measured preoperatively and postoperatively. The distribution of myelinated axons in the dorsal nerve roots was evaluated histologically. Mechanical hyperalgesia was detected in rats in which autologous nucleus pulposus was applied to the nerve root but not in those in which silk loops were used. Silk loops around the nerve root resulted in thermal hyperalgesia only in rats in which autologous nucleus pulposus was applied to the nerve root. Fewer large myelinated fibers were seen in the rats in which silk loops were used. Although a silk loop around the nerve root was not sufficient to produce hyperalgesia, supplemental application of autologous nucleus pulposus to the nerve root produced thermal hyperalgesia. It is possible that mechanical constriction of the nerve root alters the pain-related behavior elicited by chemical factors from the nucleus pulposus.     

2000 Volvo Award winner in basic science studies: Exogenous tumor necrosis factor-alpha mimics nucleus pulposus-induced neuropathology. Molecular, histologic, and behavioral comparisons in rats

STUDY DESIGN: This study tested the hypothesis that the 17-kDa form of tumor necrosis factor-alpha is the pathophysiologic agent expressed by herniated nucleus pulposus in vivo that is primarily responsible for the histologic and behavioral manifestations of experimental sciatica associated with herniated lumbar discs. OBJECTIVE: The authors determined the molecular weight and concentration of active tumor necrosis factor-alpha in rat herniated disc and used exogenous tumor necrosis factor-alpha at the same molecular weight to study its neuropathologic effect on rat nerve root and dorsal root ganglion preparations in vivo. SUMMARY OF BACKGROUND DATA: Expressed by herniated nucleus pulposus in culture, tumor necrosis factor-alpha causes neuropathologic injury in nerve roots and neuropathic pain states in which mechanical allodynia is seen in response to peripheral stimuli. METHODS: Western blotting was used to identify the molecular weight of the operative tumor necrosis factor-alpha protein form, and measures of optical density were used for semiquantitative determination of concentration. Plastic-embedded nerve roots and dorsal root ganglion were used for neuropathologic evaluation, and von Frey stimulation was used to quantify mechanical allodynia. RESULTS: The 17-kDa form of tumor necrosis factor-alpha is expressed by herniated nucleus pulposus at a concentration of approximately 0.48 ng per herniated rat lumbar disc. Exogenous tumor necrosis factor-alpha applied in vivo to rat nerve roots produced neuropathologic changes and behavior deficits that mimicked experimental studies with herniated nucleus pulposus applied to nerve roots. CONCLUSIONS: The data reinforce other evidence that tumor necrosis factor-alpha is involved in mechanisms of neuropathic pain.     

Role of leukocytes in radicular pain secondary to herniated nucleus pulposus

Some studies have assessed inflammatory cells such as macrophages, lymphocytes, and neutrophils in herniated lumbar disc tissues using histologic analysis. However, there is no consensus regarding the relationships between clinical symptoms, including radicular pain and the presence of inflammatory cells. It has been shown that autologous nucleus pulposus relocated on the lumbar nerve root in rats produces time dependent and reversible mechanical hyperalgesia, which is thought to be a pain related behavior in peripheral neuropathic pain models. The purpose of this study was to determine whether leukocytes play a role in the mechanical hyperalgesia induced by the nucleus pulposus and to characterize the role of leukocytes in radicular pain attributable to lumbar disc herniation. Nitrogen mustard was used to induce and evaluate leukocytopenia in rats. Sensitivity to mechanical noxious stimuli was measured quantitatively, and inflammatory cells in granulation tissue around the nerve root were examined histologically. The nucleus pulposus produced neither mechanical hyperalgesia nor abundant inflammatory cells in rats with nitrogen mustard induced leukocytopenia. Neuropathic pain produced by the nucleus pulposus, when placed on the nerve root, may be related to inflammatory cell infiltration induced by relocation of the nucleus pulposus, rather than the nucleus pulposus itself.     

实验性髓核突出诱致神经根性疼痛机理的探讨

目的 探索单纯自体髓核组织放置于神经根邻近,并与神经根接触后对大鼠后爪机械刺激痛觉敏感性的影响。方法 取大鼠自体尾椎髓核组织无压迫下置于腰4和腰5神经根旁并与神经根相接触,术后不同的时间点观察大鼠双侧后爪机械刺激敏感性的变化;同时采用HE染色方法观察髓核组织和神经根的变化。结果 无明显机械压迫情况下,自体髓核组织与神经根接触后可诱导大鼠术侧后爪出现明显的机械性痛觉敏感性的升高;HE染色显示髓核组织发生了明显的炎性改变,邻近神经根出现空泡变性。结论 髓核组织自身介导的炎症反应可能参与机械性痛觉敏感性的发生。除机械因素外,突出髓核组织发生的炎症反应也可能是腰椎间盘突出所致坐骨神经痛的原因。