韓光,李璐,趙平
(中國(guó)醫(yī)科大學(xué)附屬盛京醫(yī)院麻醉科,沈陽(yáng) 110004)
高壓氧對(duì)神經(jīng)病理性疼痛大鼠p38 MAPK信號(hào)通路的影響
韓光,李璐,趙平
(中國(guó)醫(yī)科大學(xué)附屬盛京醫(yī)院麻醉科,沈陽(yáng) 110004)
目的探討高壓氧對(duì)神經(jīng)病理性疼痛大鼠p38 MAPK信號(hào)通路的影響,從而明確其作用機(jī)制。方法實(shí)驗(yàn)分為2部分,每部分選用30只SD大鼠,又隨機(jī)分為3組:假手術(shù)組(S組)、坐骨神經(jīng)慢性縮窄組(CCI組)和高壓氧組(HBO組),每組10只。第一部分實(shí)驗(yàn)測(cè)定術(shù)后3,7,14,28 d疼痛行為學(xué)指標(biāo),并在術(shù)后28 d取脊髓標(biāo)本W(wǎng)estern blot方法檢測(cè)磷酸化p38表達(dá),免疫組化法檢測(cè)P2X4受體;第二部分實(shí)驗(yàn)先對(duì)各組大鼠行腰段鞘內(nèi)置管,并將p38 MAPK信號(hào)通路阻斷劑(SB203580)連續(xù)注入蛛網(wǎng)膜下腔中,測(cè)定阻斷p38 MAPK信號(hào)通路后3,7,14,28 d疼痛行為學(xué)指標(biāo)及術(shù)后28 d免疫組化法檢測(cè)P2X4受體。結(jié)果第一部分實(shí)驗(yàn)中CCI組、HBO組大鼠疼痛行為學(xué)評(píng)分較S組明顯降低(P<0.05),且CCI組比HBO組降低顯著(P<0.05)。CCI組、HBO組的磷酸化p38及P2X4受體含量較S組增加(P<0.05),且CCI組磷酸化p38及P2X4受體的表達(dá)比HBO組顯著增加(P<0.05)。第二部分實(shí)驗(yàn)中大鼠p38 MAPK信號(hào)通路抑制后,CCI組、HBO組疼痛行為學(xué)評(píng)分無(wú)統(tǒng)計(jì)學(xué)差異(P>0.05),但與未給抑制劑第一部分實(shí)驗(yàn)的CCI組、HBO組比較明顯增高(P<0.05);CCI組及HBO組的P2X4受體表達(dá)比S組顯著增高(P<0.05),但2組間比較無(wú)統(tǒng)計(jì)學(xué)差異(P>0.05)。結(jié)論高壓氧可能通過(guò)P2X4受體介導(dǎo)的p38 MAPK信號(hào)通路影響神經(jīng)病理性疼痛大鼠。
高壓氧;坐骨神經(jīng)結(jié)扎;p38;P2X4受體
網(wǎng)絡(luò)出版地址
神經(jīng)病理性疼痛發(fā)病機(jī)制十分復(fù)雜,治療效果欠佳。近年來(lái)很多報(bào)道[1]顯示,外周神經(jīng)損傷后,絲裂原激活的蛋白激酶(p38 MAPK)通路的某些重要信號(hào)蛋白、受體發(fā)生明顯變化。高壓氧是一種新型、無(wú)創(chuàng)、有效的治療手段,已廣泛應(yīng)用在神經(jīng)病理性疼痛領(lǐng)域,但高壓氧的作用機(jī)制還不是很清楚。本研究通過(guò)研究p38 MAPK信號(hào)通路中P2X4受體在高壓氧抗神經(jīng)病理性疼痛中的作用,深入了解其在高壓氧抗神經(jīng)病理性疼痛的信號(hào)傳導(dǎo)作用機(jī)制,從而為發(fā)現(xiàn)更具有針對(duì)性的疼痛治療靶點(diǎn)提供依據(jù)。
1.1一般資料
雄性SD大鼠60只,體質(zhì)量280~320 g,由中國(guó)醫(yī)科大學(xué)盛京醫(yī)院實(shí)驗(yàn)動(dòng)物中心提供。實(shí)驗(yàn)分為2部分,每部分30只SD大鼠。各部分又隨機(jī)均分為3組:假手術(shù)組(S組),暴露卻不結(jié)扎坐骨神經(jīng);坐骨神經(jīng)慢性縮窄(chronic constrictive injury,CCI)組,右側(cè)坐骨神經(jīng)結(jié)扎;高壓氧(hyperbaric oxygen,HBO)組,術(shù)后第1天實(shí)施HBO,連續(xù)進(jìn)行5 d。
1.2方法
1.2.1CCI模型的制備:腹腔注射1%戊巴比妥鈉(40 mg/kg)麻醉,在右后肢外側(cè)找尋坐骨神經(jīng)主干,分離出坐骨神經(jīng),4?0絲線(xiàn)圍繞并輕輕結(jié)扎坐骨神經(jīng),使神經(jīng)外膜稍稍受壓,同時(shí)肌肉出現(xiàn)快速收縮抽搐。最后分層縫合,歸籠飼養(yǎng)。假手術(shù)組的大鼠僅暴露右側(cè)坐骨神經(jīng)。
1.2.2實(shí)驗(yàn)鼠的HBO處理:HBO組大鼠被放入艙內(nèi),艙內(nèi)先進(jìn)行純氧洗艙,勻速加壓至0.25 MPa,高壓狀態(tài)下停留1 h,又勻速減到常壓。1次/d,連續(xù)5 d。其他組大鼠放置在艙內(nèi),模擬高壓氧組的實(shí)驗(yàn)環(huán)境與條件。
1.2.3鞘內(nèi)p38抑制劑大鼠模型的制備:第2部分大鼠腹腔注射1%戊巴比妥鈉(40 mg/kg)麻醉,將大鼠俯臥位固定,剃毛、消毒、鋪巾,在兩側(cè)骼棘聯(lián)線(xiàn)上方L3?4間隙行縱行切口,暴露L3、L4棘突。分離組織后,再用細(xì)針穿透黃韌帶,置入一根導(dǎo)管,使腦脊液從導(dǎo)管慢慢流出,固定導(dǎo)管后觀察2 d,選取無(wú)感覺(jué)及運(yùn)動(dòng)障礙的大鼠。通過(guò)導(dǎo)管,定時(shí)定量給予p38抑制劑—SB203580(2.5 μg),連續(xù)5 d。
將大鼠腹腔麻醉后,在左心室插管,灌注生理鹽水沖洗,待流出液無(wú)血性液體后,取腰段L4~6脊髓,-80℃冰箱保存一部分,其余的浸泡在4%多聚甲醛中待用。
1.3觀察指標(biāo)
1.3.1大鼠疼痛行為學(xué)評(píng)分的測(cè)定:在術(shù)后3、7、14、28 d上午9:00?12:00進(jìn)行大鼠疼痛行為學(xué)檢測(cè)。(1)機(jī)械性縮足反射閾值(mechanical withdrawal threthold,MWT),將大鼠置金屬網(wǎng)格上,罩上透明玻璃罩。使用von Frey纖維刺激大鼠結(jié)扎側(cè)足底的中部,使纖維絲在6~8 s內(nèi)彎成S形,觀察大鼠是否縮足。(2)熱刺激爪退縮閾值(thermal withdrawal laten?cy,TWL),使用熱測(cè)痛儀將聚光燈產(chǎn)生的光輻射焦點(diǎn)對(duì)準(zhǔn)大鼠結(jié)扎側(cè)足底中部,當(dāng)大鼠抬腿時(shí)為爪退縮閾值。連續(xù)測(cè)量5次,取平均值。
1.3.2Western blot方法測(cè)定組織中磷酸化p38含量:用ECL發(fā)光法試劑盒(SW2040,北京索萊寶科技有限公司)顯色,結(jié)果采用美國(guó)BIO?RAD凝膠成像系統(tǒng)(Gel DocTM XR,美國(guó)BIO?RAD公司)拍照,用Quantity One 1?D軟件(美國(guó)BIO?RAD公司)分析,記錄每條蛋白電泳帶的灰度值。
1.3.3免疫組化方法觀察P2X4受體含量:4%多聚甲醛固定并包埋大鼠脊髓組織,加入P2X4抗體及二抗,光鏡觀察,棕色染色的為陽(yáng)性細(xì)胞。顯微照相及圖像分析應(yīng)用U?MCB Olympus圖像采集系統(tǒng)、METAMORPH/COOL SNAP+X/AX70顯微(熒光)圖像分析系統(tǒng)(VIC/ROPER OLYMPUS)US/JP對(duì)切片進(jìn)行分析處理,每只大鼠取4張切片,測(cè)定陽(yáng)性細(xì)胞數(shù)值,放大400倍照相。
1.4統(tǒng)計(jì)學(xué)分析
2.1各組大鼠疼痛行為學(xué)評(píng)分的測(cè)定結(jié)果比較
第一部分大鼠CCI術(shù)后CCI組、HBO組疼痛行為學(xué)評(píng)分較S組明顯降低,且CCI組比HBO組降低更明顯(均P<0.05)。第二部分大鼠在給予SB203580后,S組MWT及TWL值無(wú)明顯變化,但CCI組與HBO組大鼠MWT及TWL值顯著增加(P<0.05),但CCI組與HBO組之間比較無(wú)統(tǒng)計(jì)學(xué)差異(P>0.05)。見(jiàn)表1。
2.2各組大鼠磷酸化p38表達(dá)比較
第一部分大鼠Western blot結(jié)果顯示:與S組(0.61±0.08)比較,CCI組(0.98±0.08)與HBO組(0.89±0.11)磷酸化p38表達(dá)上升(P<0.05)。但HBO組大鼠磷酸化p38血清含量顯著低于CCI組(P<0.05),見(jiàn)圖1。
2.3各組大鼠P2X4受體表達(dá)比較
兩部分試驗(yàn)中CCI組與HBO組大鼠P2X4受體與S組比較在脊髓表達(dá)增加。第一部分實(shí)驗(yàn)CCI組增加均較HBO組顯著(P<0.05),第二部分實(shí)驗(yàn)這2組無(wú)統(tǒng)計(jì)學(xué)差異(P>0.05),見(jiàn)表2,圖2、3。
表1 各組大鼠疼痛行為學(xué)評(píng)分的測(cè)定結(jié)果比較(±s)Tab.1 Pain?related behavior of rats in each group(±s)
表1 各組大鼠疼痛行為學(xué)評(píng)分的測(cè)定結(jié)果比較(±s)Tab.1 Pain?related behavior of rats in each group(±s)
1)P<0.05 vs group S in the same part;2)P<0.05 vs group CCI in the same part.
Group MWT(g)TWL(s)-1 d 3 d 7 d 14 d 28 d -1 d 3 d 7 d 14 d 28 d Part 1 S 9.5±0.2 8.5±0.3 8.1±0.2 8.7±0.4 9.2±0.2 18.3±0.3 16.0±0.2 17.1±0.4 16.8±0.3 17.4±0.2 CCI 9.8±0.2 3.3±0.81) 2.6±0.71) 3.0±0.51) 3.9±0.41) 18.2±0.2 8.5±0.71) 8.2±0.61) 8.7±0.51) 8.8±0.51)HBO 9.7±0.2 5.9±0.51),2) 5.3±0.41),2) 6.3±0.61),2) 7.5±0.51),2) 18.1±0.2 10.8±0.91),2) 11.5±0.71),2) 11.5±0.41),2) 13.1±0.31),2)Part 2 S 9.3±0.1 8.1±0.2 8.7±0.3 9.0±0.3 9.2±0.2 18.3±0.2 16.0±0.3 17.1±0.4 16.8±0.2 17.4±0.3 CCI 9.6±0.2 7.1±0.51) 6.8±0.31) 6.9±0.41) 7.2±0.51) 18.2±0.3 12.0±0.51) 12.3±0.61) 12.0±0.41) 12.5±0.31)HBO 9.6±0.2 7.0±0.51) 7.0±0.41) 7.1±0.61) 7.3±0.41) 18.1±0.2 12.5±0.51) 12.7±0.71) 12.1±0.31) 13.1±0.41)
圖1 第一部分各組大鼠磷酸化p38的表達(dá)結(jié)果Fig.1 The phosphorylative p38 expression of rats in three groups of part one
表2 各組大鼠P2X4受體表達(dá)比較Tab.2 P2X4 receptor expression of rats in groups
1)P<0.05 vs group S in the same part;2)P<0.05 vs group HBO in the same part.
圖2 第一部分各組大鼠P2X4受體的免疫組化結(jié)果×400Fig.2 P2X4 receptor immunohistochemistry expression in spinal cord in each group of part one×400
圖3 第二部分各組大鼠在給予p38抑制劑后P2X4受體的免疫組化結(jié)果×400Fig.3 P2X4 receptor immunohistochemistry expression after SB203580 administration in spinal cord in each group of part two×400
神經(jīng)損傷后,脊髓中磷酸化p38 MAPK免疫組化陽(yáng)性細(xì)胞顯著增加,尤其以p38 MAPK磷酸化水平明顯增加[2]。在多種炎性疼痛的動(dòng)物模型中,p38 MAPK參與炎性痛覺(jué)過(guò)敏的形成,并可以通過(guò)多種機(jī)制和信號(hào)系統(tǒng)發(fā)揮作用[3?5]。文獻(xiàn)[6]報(bào)道皮下注射辣椒素可引起疼痛,同時(shí)伴隨周?chē)つw的p38受體MAPK增加,使用p38 MAPK抑制劑SB203580就能達(dá)到鎮(zhèn)痛的作用。同時(shí)可以抑制炎性組織中P2X4的增加并減輕動(dòng)物的機(jī)械性痛敏及熱痛敏[7?8]。因此我們推測(cè)p38 MAPK信號(hào)通路可能通過(guò)調(diào)節(jié)P2X4受體蛋白的釋放,參與疼痛的形成。
HBO能增加減輕神經(jīng)水腫,使組織抗氧化,加速自由基的清除,提高攜氧能力、產(chǎn)生ATP,促進(jìn)毛細(xì)血管再生,緩解疼痛[9?10]。有學(xué)者[11?12]認(rèn)為HBO的神經(jīng)保護(hù)作用機(jī)制可能是抑制氧化應(yīng)激反應(yīng)。因?yàn)镠BO可降低白細(xì)胞的大量聚集,降低循環(huán)中炎性因子的釋放[13?14]。它在早期抑制炎性因子的產(chǎn)生與釋放方面有著重要的作用。最近有研究[15]表明,HBO通過(guò)增高腦源性神經(jīng)營(yíng)養(yǎng)因子的水平,抑制p38 MAPK信號(hào)通路,達(dá)到腦保護(hù)。說(shuō)明 p38 MAPK信號(hào)通路調(diào)節(jié)的細(xì)胞功能在腦保護(hù)中可能扮演了重要的角色,它為HBO的神經(jīng)保護(hù)作用機(jī)制的闡明開(kāi)辟了新的道路。本研究結(jié)果表明:與S組大鼠相比CCI組及HBO組大鼠磷酸化p38水平顯著增加,說(shuō)明外周神經(jīng)損傷后p38 MAPK被激活。磷酸化p38 MAPK伴隨痛覺(jué)過(guò)敏,在術(shù)后3 d開(kāi)始升高。P38 MAPK被阻斷后,疼痛明顯緩解。但是,p38 MAPK只是MAPK信號(hào)通路眾多亞族中的一種,MAPK信號(hào)通路的上下游分子也需要進(jìn)一步尋找。另外,高壓氧是否通過(guò)減少P2X4受體表達(dá)影響p38 MAPK信號(hào)通路的作用還不清楚,仍需要進(jìn)行深入探討。
曾有報(bào)道[16]在甲醛造成的大鼠致炎性痛模型中,脊髓小膠質(zhì)細(xì)胞的P2X4受體上調(diào)。P2X4受體蛋白隨時(shí)間逐漸增加,這種變化與神經(jīng)損傷后引起的痛覺(jué)超敏變化相一致。目前外周神經(jīng)損傷后,脊髓小膠質(zhì)細(xì)胞P2X4受體調(diào)控的機(jī)制還不是很清楚,可能與小膠質(zhì)細(xì)胞活化后P2X4受體mRNA及蛋白的轉(zhuǎn)錄有關(guān)[17?18]。已有研究[19?20]表明,神經(jīng)損傷后通過(guò)激活p38 MAPK、ERK等細(xì)胞內(nèi)信號(hào)分子進(jìn)一步活化P2X4受體轉(zhuǎn)錄,反之應(yīng)用這些分子的抑制劑可有效減輕疼痛,預(yù)防脊髓神經(jīng)痛覺(jué)超敏。本研究證明高壓氧能有效減少P2X4受體的表達(dá),而且這種抗神經(jīng)病理性疼痛作用在給予P38 MARK抑制劑后變得不明顯,提示它很可能通過(guò)P38 MARK信號(hào)通路起作用。
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(編輯武玉欣)
Effect of Hyperbaric Oxygen on p38 MAPK Signal Transduction Pathway in Neuropathic Rats
HAN Guang,LI Lu,ZHAO Ping
(Department of Anesthesiology,Shengjing Hospital,China Medical University,Shenyang 110004,China)
ObjectiveTo investigate the effect of hyperbaric oxygen(HBO)on p38 MAPK signal pathway in neuropathic pain,and explore its mechanism.MethodsThe experiment was divided into two parts with thirty SD rats in each part.Each part was then randomly divided into 3 groups:sham operation group(S group),chronic constriction group(CCI group)and hyperbaric oxygen group(HBO group),with 10 rats in each group.Part one:Pain?related behavior were detected on 3 day,7 day,14 day,28 day after operation.Phosphorylative p38 was detected by Western blot method and the P2X4 receptor was detected by immunohistochemistry method on the 28th day.Part two:All the rats were treated with SB203580.Pain?related behavior were detected on 3 day,7 day,14 day,28 day after operation.P2X4 receptor was detected by immunohistochem?istry method on the 28th day.ResultsCCI and HBO groups were significantly lower than S group in pain?related behaviors(P<0.05).CCI group was significantly lower than that in HBO group(P<0.05).The content of phosphorylative p38 and P2X4 receptor in CCI and HBO group were increased(P<0.05),and the expression of phosphorylative p38 and P2X4 in CCI group was significantly increased than that in HBO group (P<0.05).When p38 MAPK was inhibited,pain?related behavior in HBO and CCI group increased significantly than the pain?related behavior of HBO and CCI group in Part 1(P<0.05).But the difference between group CCI and HBO was not significant(P>0.05).Though the expression of P2X4 receptor in CCI group and HBO group was significantly higher than that in S group(P<0.05),the difference between group CCI and HBO was not significant(P>0.05).ConclusionHyperbaric oxygen therapy can affect the expression of p38 MAPK through P2X4 receptor in rats of neuropathic pain.
hyperbaric oxygen;chronic constrictive injury;p38;P2X4 receptor
R614
A
0258-4646(2016)08-0723-05
10.12007/j.issn.0258?4646.2016.08.013
沈陽(yáng)市科學(xué)技術(shù)計(jì)劃(F15?199?1?35)
韓光(1978-),女,副教授,碩士.
趙平,E-mail:zhaop@sj?hospital.org
2016-01-11
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