喻海春 孫廣運(yùn)
[摘要] 神經(jīng)病理性疼痛主要是神經(jīng)系統(tǒng)損傷而導(dǎo)致的慢性疼痛,由于神經(jīng)病理性疼痛的發(fā)病機(jī)制較為復(fù)雜,目前臨床上對(duì)神經(jīng)病理性疼痛確切的發(fā)病機(jī)制仍尚未明了,因而現(xiàn)階段臨床上仍缺乏有效的治療藥物,故臨床上需要加強(qiáng)對(duì)神經(jīng)病理性疼痛的研究。本文主要敘述神經(jīng)病理性疼痛的發(fā)病機(jī)制及治療現(xiàn)狀,通過對(duì)國(guó)外神經(jīng)病理性疼痛實(shí)驗(yàn)的綜述分析,探討神經(jīng)病理性疼痛的臨床治療方法,為臨床提供理論指導(dǎo)。
[關(guān)鍵詞] 神經(jīng)病理性疼痛;實(shí)驗(yàn);發(fā)病機(jī)制;治療現(xiàn)狀
[中圖分類號(hào)] R285.5 [文獻(xiàn)標(biāo)識(shí)碼] A [文章編號(hào)] 1674-0742(2015)09(a)-0104-02
Experimental on Neuropathic Pain and Its Treatment
YU Hai-chun, SUN Guang-yun
Department of Anesthesiology, Affiliated Hospital of Luzhou Medical College, Luzhou, Sichuan Province, 646000 China
[Abstract] Neuropathic pain is chronic pain caused by nervous system damage, and its pathogenesis is still an unclear due to its complexity. Therefore at this stage therapeutic agents are still lack, and it is necessary for us to strengthen its research. The paper mainly describes the pathogenesis of this disease and its treatment status, and by reviewing foreign experiments and discussing its treatment plan, provides theoretical guidance to clinical practice.
[Key words] Neuropathic pain; Experiment; Pathogenesis; Treatment status
神經(jīng)病理性疼痛的發(fā)病率較高,常見于40~60歲中老年人群。研究認(rèn)為神經(jīng)病理性疼痛的發(fā)生與自身免疫性疾病、感染、創(chuàng)傷、藥物使用不當(dāng)?shù)纫蛩赜嘘P(guān)[1]?;颊邥?huì)表現(xiàn)出自發(fā)性疼痛、感覺異常、痛覺過敏等癥狀體征,且疼痛感明顯、持續(xù)時(shí)間長(zhǎng),對(duì)患者的日常生活、工作與學(xué)習(xí)產(chǎn)生十分大的影響。神經(jīng)病理性疼痛的發(fā)病機(jī)制十分復(fù)雜,治療的難度較大,目前臨床上主要使用鎮(zhèn)痛藥、抗抑郁藥以及NMDA拮抗劑治療神經(jīng)病理性疼痛[2],臨床效果并不理想,且不良反應(yīng)發(fā)生率高,臨床應(yīng)用受到了限制。本文主要對(duì)神經(jīng)病理性疼痛的實(shí)驗(yàn)、機(jī)制及治療現(xiàn)狀展開綜述,現(xiàn)報(bào)道如下。
1 神經(jīng)病理性疼痛的實(shí)驗(yàn)、機(jī)制
研究顯示Sirt1在神經(jīng)損傷修復(fù)的過程中發(fā)揮出重要作用,主要是在神經(jīng)損傷修復(fù)中起到軸突保護(hù)的作用。實(shí)驗(yàn)通過預(yù)先給予Sirt1 激動(dòng)劑白藜蘆醇治療,軸突在切斷后的分解明顯較少,而降低Sirt1的活性則阻斷了NAD+依賴的軸突保護(hù)。實(shí)驗(yàn)發(fā)現(xiàn)Sirt1激動(dòng)劑白藜蘆醇能夠減輕小鼠心肌缺血再灌注、兔脊髓損傷,抑制神經(jīng)元的死亡,降低學(xué)習(xí)功能損害,并可有效降低細(xì)胞毒性[3]。這些實(shí)驗(yàn)結(jié)果提示我們可以通過調(diào)節(jié)Sirt1活性來治療神經(jīng)病理性疼痛。
有研究學(xué)者認(rèn)為神經(jīng)病理性疼痛的主要發(fā)病機(jī)制是外周神經(jīng)系統(tǒng)和中樞神經(jīng)系統(tǒng)的改變,且隨著時(shí)間的推移,神經(jīng)病理性疼痛的發(fā)病機(jī)制可能發(fā)生變化,因而臨床上普遍認(rèn)為外周機(jī)制和中樞機(jī)制是神經(jīng)病理性疼痛發(fā)生、發(fā)展、維持的重要原因[4]。
外周機(jī)制主要包括異位放電、炎癥反應(yīng)和交感一感覺神經(jīng)系統(tǒng)的耦合三方面。①異位放電:外周神經(jīng)發(fā)生損傷后,在相應(yīng)的損傷區(qū)域會(huì)產(chǎn)生大量的異位放電,而異位放電會(huì)導(dǎo)致脊髓的敏感性提高而引起神經(jīng)痛的癥狀。目前對(duì)異位放電產(chǎn)生的具體機(jī)制尚闡明,研究認(rèn)為多離子通道大量聚集在損傷區(qū)域、胞體膜附近使得膜重塑可能是異位放電產(chǎn)生的原因。實(shí)驗(yàn)表明損傷區(qū)神經(jīng)元胞體膜上Ca2+、K+、Na+離子通道的變化引起了異位放電,同時(shí)膜電位閾下震蕩也參與了異位放電產(chǎn)生的過程。②炎癥反應(yīng):炎癥反應(yīng)參與外周神經(jīng)損傷后誘發(fā)的神經(jīng)痛中[5]。緩激肽、5-HT、組胺等化學(xué)介質(zhì)的釋放激活了炎性細(xì)胞,導(dǎo)致血漿蛋白滲出與血管的舒張,造成高閾值的傷害感受器化學(xué)致敏,進(jìn)而傳導(dǎo)強(qiáng)度較低的疼痛。③交感一感覺神經(jīng)系統(tǒng)的耦合[6]:周圍神經(jīng)發(fā)生損傷后,一方面受損的神經(jīng)元和周圍未損傷的神經(jīng)元對(duì)交感神經(jīng)分泌出的腎上腺素產(chǎn)生反應(yīng),另一方面交感神經(jīng)節(jié)后纖維傳導(dǎo)興奮,會(huì)導(dǎo)致感覺神經(jīng)元的敏感性提高。
中樞機(jī)制主要包括中樞敏化、骨髓的解剖重構(gòu)、中樞去抑制三方面。①中樞敏化:神經(jīng)損傷和炎癥反應(yīng)會(huì)刺激骨髓的興奮性,臨床上將其稱為“中樞敏化”[7]。興奮性氨基酸的分泌會(huì)激活NMDA和非NMDA受體,導(dǎo)致突觸的活動(dòng)頻率提升,使得神經(jīng)元放電量增加,在神經(jīng)損傷和炎癥反應(yīng)發(fā)生時(shí)這些神經(jīng)元的可塑性變化是引起疼痛的主要原因。②骨髓的解剖重構(gòu):高閾值的C纖維位于脊髓后角的第II層,低高閾值的Aβ纖維位于脊髓后角的第III和IV層。但是當(dāng)神經(jīng)發(fā)生損傷后,Aβ纖維會(huì)占據(jù)脊髓后角的第II層,和二級(jí)神經(jīng)元形成突觸聯(lián)系[8]。③中樞去抑制:GABA、甘氨酸等抑制性神經(jīng)遞質(zhì)與相應(yīng)受體結(jié)合后起到突觸前作用和突觸后作用,抑制痛覺信號(hào)傳遞;當(dāng)神經(jīng)系統(tǒng)發(fā)生損傷后,下行抑制系統(tǒng)功能受到影響,抑制去甲腎上腺素與5-HT的效能,導(dǎo)致脊髓背角敏化。
2 神經(jīng)病理性疼痛的治療現(xiàn)狀
目前,臨床上對(duì)神經(jīng)病理性疼痛的治療主要包括藥物治療、介入性治療、姑息替代治療等。①藥物治療:三環(huán)類抗抑郁藥、抗癲癇藥因其改善神經(jīng)病理性疼痛的效果顯著,被作為治療神經(jīng)病理性疼痛的一線藥物。而阿片類藥物和曲馬多則是作為治療神經(jīng)病理性疼痛的二線藥物,阿片類藥物因其長(zhǎng)期用藥的安全性不高,且容易成癮,故沒有被列入一線藥物,Ney JP等[9]研究學(xué)者認(rèn)為曲馬多的鎮(zhèn)痛效果不如阿片類藥物,但其用藥的安全性相對(duì)較高。除一線藥物,部分抗抑郁藥物如帕羅西汀、安非他酮等以及部分抗癲癇藥物如奧卡西平、卡馬西平等、NMDA受體拮抗劑則是作為神經(jīng)病理性疼痛的三線藥物,三線藥物是在一線或二線藥物治療效果不理想或患者無法耐受的情況下應(yīng)用。②介入性治療:神經(jīng)病理性疼痛的介入性治療包括外科手術(shù)、脊髓電刺激、神經(jīng)毀損、注射治療等。但是Niccola P等[10]學(xué)者認(rèn)為介入性治療在適用人群、治療部位、藥物的選擇和藥物的用量等方面存在不確定性,因而治療效果也難以準(zhǔn)確評(píng)估,所以現(xiàn)階段尚缺乏統(tǒng)一的標(biāo)準(zhǔn)和方案。③姑息替代治療:姑息替代治療是神經(jīng)病理性疼痛非傳統(tǒng)方法,能夠有效保持和恢復(fù)功能、防止廢用性萎縮的發(fā)生。脊柱推拿和按摩能夠減輕肩周、腰部的疼痛,同時(shí)對(duì)頸部、纖維肌疼痛也有一定的緩解作用;針灸治療不僅能夠改善患者的心理和軀體功能,同時(shí)在緩解下腰、頸部、纖維肌疼痛中起著重要作用;經(jīng)皮神經(jīng)電刺激是上世紀(jì)70年代應(yīng)用于疼痛的治療中,但是目前對(duì)經(jīng)皮神經(jīng)電刺激緩解疼痛作用的仍然存在一定的爭(zhēng)議,Wang C等[11]學(xué)者認(rèn)為這可能與經(jīng)皮神經(jīng)電刺激的治療參數(shù)變異巨大存在聯(lián)系。
高壓氧是臨床上應(yīng)用十分廣泛的治療手段,Gu N等[12]學(xué)者認(rèn)為高壓氧能夠保護(hù)神經(jīng)組織、促進(jìn)受損神經(jīng)的恢復(fù)、抑制炎癥反應(yīng),廣泛應(yīng)用于CO中毒、周圍神經(jīng)損傷、腦缺血等疾病的治療,然而目前關(guān)于高壓氧治療神經(jīng)病理性疼痛的相關(guān)報(bào)道較少。Sirt1是Ⅲ類去乙?;?,能夠活化關(guān)鍵的轉(zhuǎn)錄因子,Sirt1水平受到能量平衡、氧化應(yīng)激的影響,高壓氧則通過釋放活性氧簇來減輕氧化應(yīng)激反應(yīng),提高Sirt1水平,有利于損傷的修復(fù),表明Sirt1可能參與高壓氧的鎮(zhèn)痛機(jī)制。
3 結(jié)語
據(jù)調(diào)查顯示近些年我國(guó)神經(jīng)病理性疼痛的患病人數(shù)日益增加,受到各個(gè)部分的高度重視,加強(qiáng)對(duì)神經(jīng)病理性疼痛的發(fā)病機(jī)制、治療方法的研究十分有必要。本次研究結(jié)果認(rèn)為外周機(jī)制和中樞機(jī)制是神經(jīng)病理性疼痛發(fā)生、發(fā)展、維持的重要原因。同時(shí)患者若接受藥物治療、介入性治療、姑息替代治療的效果不理想時(shí),可以結(jié)合高壓氧進(jìn)行治療,從而進(jìn)一步改善緩解患者的癥狀。
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(收稿日期:2015-06-07)