王海峰,丁宏霞,胡灃,洪鶴,李葛巍,符來(lái)想,方健
海水浸泡對(duì)大鼠坐骨神經(jīng)損傷后促炎因子表達(dá)的影響及早期干預(yù)效果觀察
王海峰,丁宏霞,胡灃,洪鶴,李葛巍,符來(lái)想,方健
目的探討海水浸泡加重坐骨神經(jīng)損傷的機(jī)制和甲潑尼龍的保護(hù)作用,為海水浸泡坐骨神經(jīng)損傷的臨床治療提供實(shí)驗(yàn)依據(jù)。方法健康雄性清潔級(jí)SD大鼠192只,隨機(jī)分為假手術(shù)組(A組)、損傷對(duì)照組(B組)、損傷+海水浸泡組(C組)、甲潑尼龍治療組(D組),每組48只。B、C、D組制作大鼠坐骨神經(jīng)鉗夾傷模型,C、D組制模成功后浸入人工海水1h,D組傷后給予甲潑尼龍20mg/(kg·d)尾靜脈注射(共2d)。分別于傷后3d及1、2、4周采用坐骨神經(jīng)功能指數(shù)(SFI)評(píng)定神經(jīng)運(yùn)動(dòng)功能,然后取大鼠坐骨神經(jīng)組織,采用RT-PCR檢測(cè)IL-1β、IL-6和TNF-α mRNA表達(dá)水平,免疫組織化學(xué)法檢測(cè)IL-1β、IL-6和TNF-α蛋白表達(dá)情況。結(jié)果傷后3d及1、2、4周A組坐骨神經(jīng)功能指數(shù)無(wú)明顯變化,而B(niǎo)、C、D組坐骨神經(jīng)功能指數(shù)逐漸升高,且B、D組明顯高于C組,差異有統(tǒng)計(jì)學(xué)意義(P<0.05)。傷后3d及1、2、4周A組坐骨神經(jīng)組織中IL-1β、IL-6、TNF-α mRNA表達(dá)水平均較低,而B(niǎo)、C、D組IL-1β、IL-6 mRNA表達(dá)水平逐漸下降,且傷后3d及1、2周時(shí)B、D組表達(dá)水平明顯低于C組(P<0.05),傷后4周時(shí)3組間比較差異無(wú)統(tǒng)計(jì)學(xué)意義(P>0.05);B、C、D 組TNF-α mRNA表達(dá)水平在傷后3d及1、2周時(shí)逐漸下降,且傷后3d及1周時(shí)B、D組表達(dá)水平明顯低于C組(P<0.05),傷后2周及4周時(shí)3組間比較差異無(wú)統(tǒng)計(jì)學(xué)意義(P>0.05)。傷后3d及1、2、4周A組坐骨神經(jīng)組織中IL-1β、IL-6、TNF-α蛋白均呈陰性(–)或弱陽(yáng)性(+)表達(dá),B、C、D組在傷后3d及1周時(shí)呈強(qiáng)陽(yáng)性表達(dá),此后逐漸減弱,至傷后4周時(shí)均呈陰性(–)或弱陽(yáng)性(+)表達(dá)。結(jié)論海水浸泡增加了損傷的坐骨神經(jīng)組織中IL-1β、IL-6和TNF-α的表達(dá),導(dǎo)致炎癥反應(yīng)加重,阻礙了神經(jīng)功能恢復(fù)。甲潑尼龍可促進(jìn)海水浸泡大鼠坐骨神經(jīng)的再生,其機(jī)制可能與抑制炎性反應(yīng)有關(guān)。
海水浸泡;坐骨神經(jīng)損傷;甲潑尼龍
周圍神經(jīng)損傷與修復(fù)過(guò)程中有多種細(xì)胞因子的參與,它們參與啟動(dòng)和調(diào)控瓦勒變性、保護(hù)受損神經(jīng)元、促進(jìn)軸突生長(zhǎng)和髓鞘形成[1-3]。然而,坐骨神經(jīng)損傷合并海水浸泡后細(xì)胞因子的表達(dá)變化及早期激素干預(yù)的影響目前尚未見(jiàn)報(bào)道。本研究采用海水浸泡坐骨神經(jīng)損傷動(dòng)物模型,以IL-1β、IL-6、TNF-α等的變化為出發(fā)點(diǎn),觀察海水浸泡對(duì)坐骨神經(jīng)損傷的影響及早期使用甲潑尼龍的干預(yù)效果,旨在探討海水浸泡加重坐骨神經(jīng)繼發(fā)性損傷的機(jī)制和甲潑尼龍的保護(hù)作用,為下一步有針對(duì)性地進(jìn)行臨床治療提供實(shí)驗(yàn)依據(jù)。
1.1 人工海水的配制 采用Iannacone等[4]的配方配制人工海水,含460mmol/L NaCl,10mmol/L KCl,10mmol/L CaCl2,22mmol/L MgCl2,26mmol/L MgSO4和10mmol/L HEPES(pH7.8)。
1.2 主要試劑及儀器 Trizol試劑購(gòu)自Invitrogen公司,反轉(zhuǎn)錄試劑盒、熒光定量PCR儀購(gòu)自Thermo公司,熒光定量試劑及實(shí)驗(yàn)耗材購(gòu)自QiaGen公司,免疫組化通用型二步法檢測(cè)試劑盒及dab顯色試劑盒購(gòu)自北京中杉金橋生物技術(shù)有限公司,IL-1β、IL-6、TNF-α抗體購(gòu)自北京博奧森生物技術(shù)有限公司。引物設(shè)計(jì)及合成由Invitrogen公司完成。
1.3 實(shí)驗(yàn)動(dòng)物及分組 雄性健康清潔級(jí)SD大鼠192只,體重200~250g,由安徽醫(yī)科大學(xué)實(shí)驗(yàn)動(dòng)物中心提供,隨機(jī)分為4組(n=48)。A組(假手術(shù)組):手術(shù)暴露坐骨神經(jīng),但不進(jìn)行鉗夾損傷、海水浸泡及藥物干預(yù)處理;B組(損傷對(duì)照組):坐骨神經(jīng)行動(dòng)脈夾鉗夾壓迫致傷;C組(海水浸泡組):對(duì)坐骨神經(jīng)行鉗夾壓迫后,將大鼠浸入人工海水1h,再清創(chuàng)縫合傷口;D組(甲潑尼龍治療組):在C組的基礎(chǔ)上,傷后給予甲潑尼龍20mg/(kg·d)尾靜脈注射,共2d。實(shí)驗(yàn)大鼠均采用專門鼠籠分籠管理(每籠6 只),光照時(shí)間12h,專用鼠糧飼料喂養(yǎng),自由飲水,飼養(yǎng)管理?xiàng)l件一致。
1.4 手術(shù)處理 參照Pan等[5]的方法制作大鼠坐骨神經(jīng)鉗夾傷模型。采用3%戊巴比妥鈉(30mg/kg)腹腔注射麻醉大鼠,俯臥位固定,左側(cè)股后部正中切口,自梨狀肌下緣至膝關(guān)節(jié)上方暴露出長(zhǎng)3cm坐骨神經(jīng),于梨狀肌下1cm處用動(dòng)脈夾鉗夾坐骨神經(jīng),從相反的方向擠壓2次,每次30s。損傷遠(yuǎn)端以10-0顯微縫線作標(biāo)記。C組及D組大鼠在坐骨神經(jīng)做鉗夾壓迫后浸入人工海水1h,然后清創(chuàng)縫合傷口。鉗夾傷模型制作成功的標(biāo)志是壓榨處肉眼可見(jiàn)一明顯痕跡,神經(jīng)外膜連續(xù)而透明,大鼠小腿及足完全癱瘓,展爪反射消失。
1.5 取材和切片 分別于傷后3d及1、2、4周取材。用3%戊巴比妥鈉過(guò)量麻醉大鼠,暴露傷側(cè)坐骨神經(jīng),取損傷遠(yuǎn)端坐骨神經(jīng)1cm于–70℃凍存?zhèn)溆茫拷M6個(gè)標(biāo)本,另外6個(gè)標(biāo)本用4%多聚甲醛固定,組織脫水、透明、浸蠟、包埋、切片(厚度為4μm)。
1.6 觀測(cè)指標(biāo)
1.6.1 一般情況 包括傷后患肢傷口愈合情況,傷后患肢是否有潰瘍、缺趾等,飲食、活動(dòng)狀況以及術(shù)側(cè)肌肉萎縮情況。
1.6.2 坐骨神經(jīng)功能評(píng)定 參照Pan等[5]的方法,采用坐骨神經(jīng)功能指數(shù)(sciatic functional index,SFI)進(jìn)行評(píng)分。自制大鼠足印行走箱,長(zhǎng)50cm,寬10cm,箱底置等長(zhǎng)等寬白紙,碳素墨水浸染大鼠足底,清晰記錄大鼠雙側(cè)后足足跡3~4個(gè),選實(shí)驗(yàn)側(cè)足(E)、正常側(cè)足(N)的足印測(cè)量3個(gè)變量:足印長(zhǎng)度(PL)、足趾寬度(TS)、中間足趾距離(IT)。每組數(shù)據(jù)測(cè)量精確到毫米。測(cè)得數(shù)據(jù)后代入Bain公式,計(jì)算各組大鼠的SFI。SFI=–38.3(EPL-NPL)/ NPL+109.5(ETS-NTS)/NTS+13.3(EIT-NIT)/NIT-8.8。其中EPL為實(shí)驗(yàn)側(cè)足印長(zhǎng)度,NPL為正常側(cè)足印長(zhǎng)度,ETS為實(shí)驗(yàn)側(cè)足距寬度,NTS為正常側(cè)足距度,EIT為實(shí)驗(yàn)側(cè)中間中趾寬度,NIT為正常側(cè)中間足趾寬度。SFI=0為正常值,SFI=–100為神經(jīng)完全離斷損傷。A、B、C、D組分別于術(shù)前、傷后3d及1、2、4周隨機(jī)選取6只大鼠進(jìn)行檢測(cè)。
1.6.3 RT-PCR檢測(cè)IL-1β、IL-6和TNF-α mRNA的表達(dá) 取各組凍存的坐骨神經(jīng)組織,Trizol法抽提總RNA,按反轉(zhuǎn)錄試劑盒說(shuō)明書合成cDNA。所用引物設(shè)計(jì)及合成均由Invitrogen公司完成。IL-1β引物序列:上游5'-AATGACCTGTTCTTTGAGGCTGA-3',下游5'-CGAGATGCTGCTGTGAGATTTGA-3';IL-6引物序列:上游5'-TTCCAGCCAGTTGCCTTCT TG-3',下游5'-GGTCTGTTGTGGGTGGTATCCTC-3';TNF-α引物序列:上游5'-AGCAAACCACCAAG CGGAGG-3',下游5'-CAGCCTTGTCCCTTGAAGA GAAC-3';內(nèi)參照β-Actin引物序列:上游5'-CCCAT CTATGAGGGTTACGC-3',下游5'-TTTAATGTCAC GCACGATTTC-3'。使用SYBR Green PCR試劑盒進(jìn)行擴(kuò)增,應(yīng)用實(shí)時(shí)熒光定量PCR儀進(jìn)行實(shí)時(shí)定量PCR分析。反應(yīng)條件:95℃5min;95℃10s,60℃30s,共40個(gè)循環(huán)。PCR擴(kuò)增反應(yīng)結(jié)束后,進(jìn)行產(chǎn)物的熔解曲線分析,以保證PCR產(chǎn)物的質(zhì)量。各目的基因均與對(duì)應(yīng)的參照基因進(jìn)行校正。為減少誤差,每個(gè)樣本均重復(fù)3次,采用2–ΔΔCt法進(jìn)行相對(duì)定量分析。
1.6.4 免疫組織化學(xué)法檢測(cè)IL-1β、IL-6和TNF-α蛋白的表達(dá) 切片常規(guī)脫蠟至水,抗原修復(fù)后,依次加入兔抗大鼠抗體(1:200),生物素標(biāo)記羊抗兔IgG(1:300)和辣根酶標(biāo)記的鏈霉卵白素工作液(1:300),繼之用DAB顯色劑顯色,裱片、晾干、透明、中性樹(shù)脂封固。用PBS替代一抗作為陰性對(duì)照。選取組織結(jié)構(gòu)較好的切片,采用Olympus AX80顯微鏡觀察。蛋白表達(dá)結(jié)果判定:光鏡下觀察細(xì)胞質(zhì)中是否出現(xiàn)淡黃色、黃色或褐黃色的染色顆粒,有顆粒存在者即為陽(yáng)性細(xì)胞。根據(jù)陽(yáng)性染色的顯色程度分成如下4級(jí):陰性(–),與背景顏色一致;弱陽(yáng)性(+),細(xì)胞質(zhì)或細(xì)胞膜呈淡黃色;陽(yáng)性細(xì)胞質(zhì)或細(xì)胞膜呈黃色;強(qiáng)陽(yáng)性細(xì)胞質(zhì)或細(xì)胞膜呈深黃色或褐黃色。
1.7 統(tǒng)計(jì)學(xué)處理 數(shù)據(jù)結(jié)果以表示,采用SPSS 13.0軟件進(jìn)行統(tǒng)計(jì)分析,多組間比較采用方差分析,進(jìn)一步兩兩比較采用SNK-q法。P<0.05為差異有統(tǒng)計(jì)學(xué)意義。
2.1 一般情況 實(shí)驗(yàn)中2只大鼠因麻醉過(guò)量死亡,另外有3只海水浸泡+損傷組大鼠在浸泡后2h內(nèi)死亡,及時(shí)補(bǔ)充進(jìn)行實(shí)驗(yàn)。其余大鼠傷后全部存活,未見(jiàn)傷口感染,也未因其他部位的感染而中斷實(shí)驗(yàn)。
2.2 各組大鼠坐骨神經(jīng)功能指數(shù) A組大鼠足印無(wú)明顯變化。B、C、D組大鼠傷后足印長(zhǎng)度增大,足趾寬度及中間足趾距離均減小。B、C、D組傷后第3天坐骨神經(jīng)功能指數(shù)分別為–75.22±3.15、–87.38±2.58、–84.36±3.08,B組明顯高于C、D 組(P<0.05)。傷后1周3組坐骨神經(jīng)功能呈緩慢而漸進(jìn)的復(fù)蘇,傷后2~4周恢復(fù)幅度增大。第4周末B、C、D組坐骨神經(jīng)功能指數(shù)分別為–35.46±2.96,–60.42±2.36,–40.54±2.62,C組明顯低于B、D組(P<0.05,圖1)。
圖1 各組大鼠坐骨神經(jīng)功能指數(shù)變化Fig. 1 Changes of sciatic functional index (SFI) in each group of rats(1)P<0.05 compared with group C and group D; (2)P<0.05 compared with group B and group D
2.3 各組大鼠坐骨神經(jīng)IL-1β mRNA及蛋白的表達(dá)
A組坐骨神經(jīng)中IL-1β mRNA表達(dá)水平在各時(shí)間點(diǎn)均較低。B、C、D組坐骨神經(jīng)中IL-1β mRNA表達(dá)水平在傷后3d最高,傷后1、2周時(shí)逐漸下降,但C組表達(dá)水平均高于B、D組,差異有統(tǒng)計(jì)學(xué)意義(P<0.05)。傷后4周時(shí)各組表達(dá)水平比較差異均無(wú)統(tǒng)計(jì)學(xué)意義(P>0.05,圖2)。
A組坐骨神經(jīng)中IL-1β蛋白表達(dá)在傷后各時(shí)間點(diǎn)均為(–)-(+),B、C、D組在傷后3d及1周時(shí)呈傷后2周呈傷后4周呈(–)-(+)。D組坐骨神經(jīng)中IL-1β蛋白表達(dá)情況見(jiàn)圖3。
2.4 各組大鼠坐骨神經(jīng)IL-6 mRNA及蛋白的表達(dá)A組坐骨神經(jīng)中IL-6 mRNA表達(dá)水平在各時(shí)間點(diǎn)均較低。B、C、D組坐骨神經(jīng)中IL-6 mRNA表達(dá)水平在傷后3d最高,傷后1周、2周時(shí)逐漸下降,且2周時(shí)下降幅度較大,但C組表達(dá)水平均高于B、D組,差異有統(tǒng)計(jì)學(xué)意義(P<0.05)。傷后4周時(shí)各組表達(dá)水平比較差異均無(wú)統(tǒng)計(jì)學(xué)意義(P>0.05,圖4)。
A組坐骨神經(jīng)中IL-6蛋白表達(dá)在傷后各時(shí)間點(diǎn)均為(–)-(+),B、C、D組在傷后3d及1周時(shí)呈傷后2周呈傷后4周呈(–)-(+)。D組坐骨神經(jīng)中IL-6蛋白表達(dá)情況見(jiàn)圖5。
2.5 各組大鼠坐骨神經(jīng)TNF-α mRNA及蛋白的表達(dá) A組坐骨神經(jīng)中TNF-α mRNA表達(dá)水平在各時(shí)間點(diǎn)均較低。B、C、D組坐骨神經(jīng)中TNF-α mRNA表達(dá)水平在傷后3d最高,傷后1周時(shí)下降,但C組表達(dá)水平均高于B、D組,差異有統(tǒng)計(jì)學(xué)意義(P<0.05)。傷后2周和4周時(shí)各組表達(dá)水平比較差異均無(wú)統(tǒng)計(jì)學(xué)意義(P>0.05,圖6)。
A組坐骨神經(jīng)中TNF-α蛋白表達(dá)在傷后各時(shí)間點(diǎn)均為(–)-(+)。B、C、D組在傷后3d及1周時(shí)呈傷后2周、4周呈(–)-(+)。D組坐骨神經(jīng)中TNF-α蛋白表達(dá)情況見(jiàn)圖7。
圖2 各組大鼠坐骨神經(jīng)中IL-1β mRNA相對(duì)表達(dá)情況Fig. 2 Relative expression of IL-1β mRNA in sciatic nerve of each group of rats(1)P<0.01 compared with group B; (2)P<0.01 compared with group C
圖3 D組大鼠坐骨神經(jīng)中IL-1β蛋白表達(dá)情況(DAB ×400)Fig. 3 Expression of IL-1β protein in rat's sciatic nerve in group D (DAB ×400)A. 3 days after injury; B. 2 weeks after injury; C. 4 weeks after injury
圖4 各組大鼠坐骨神經(jīng)中IL-6 mRNA相對(duì)表達(dá)情況Fig. 4 Relative expression of IL-6 mRNA in sciatic nerve of each group of rats(1)P<0.01 compared with group B; (2)P<0.01 compared with group C
圖5 D組大鼠坐骨神經(jīng)中IL-6蛋白表達(dá)情況(DAB ×400)Fig. 5 Expression of IL-6 protein in rat's sciatic nerve in group D (DAB ×400)A. 3 days after injury; B. 2 weeks after injury; C. 4 weeks after injury
圖6 各組大鼠坐骨神經(jīng)中TNF-α mRNA相對(duì)表達(dá)情況Fig. 6 Relative expression of TNF-α mRNA in sciatic nerve of each group of rats(1)P<0.01 compared with group B; (2)P<0.01 compared with group C
圖7 D組大鼠坐骨神經(jīng)中TNF-α蛋白表達(dá)情況(DAB ×400)Fig. 7 Expression of TNF-α protein in rat's sciatic nerve in group D (DAB ×400)A. 3 days after injury; B. 2 weeks after injury; C. 4 weeks after injury
在各類海戰(zhàn)及海上事故中,人員遭受戰(zhàn)傷或外傷的機(jī)會(huì)明顯增高。海水浸泡傷口或進(jìn)入體腔會(huì)給創(chuàng)傷帶來(lái)更嚴(yán)重的問(wèn)題。目前國(guó)內(nèi)外已有學(xué)者對(duì)合并海水浸泡的開(kāi)放傷進(jìn)行研究,主要涉及海洋生物造成的皮膚損傷、海水淹溺的影響及海水浸泡體表軟組織傷、四肢骨折、腦外傷及胸腹腔開(kāi)放傷等[6-9],但目前尚未見(jiàn)海水浸泡對(duì)坐骨神經(jīng)損傷影響的相關(guān)研究。本研究采用海水浸泡坐骨神經(jīng)損傷動(dòng)物模型,觀察了海水浸泡對(duì)坐骨神經(jīng)損傷的影響及早期使用甲潑尼龍的干預(yù)效果。結(jié)果顯示,與單純鉗夾傷比較,大鼠坐骨神經(jīng)鉗夾復(fù)合海水浸泡產(chǎn)生了更嚴(yán)重的肢體功能障礙,隨后肢體功能有不同程度的恢復(fù),在傷后第2~4周恢復(fù)較快。既往有研究顯示坐骨神經(jīng)鉗夾傷后4周神經(jīng)功能即恢復(fù)至穩(wěn)定狀態(tài)[10],故本研究觀察到傷后第4周,結(jié)果顯示在第4周末C組坐骨神經(jīng)功能指數(shù)明顯低于B、D組,差異有統(tǒng)計(jì)學(xué)意義。該結(jié)果提示,海水浸泡加重了坐骨神經(jīng)損傷,阻礙了神經(jīng)運(yùn)動(dòng)功能的恢復(fù),早期激素治療有利于坐骨神經(jīng)功能的恢復(fù)。
海水的高滲、高堿、低溫及細(xì)菌是比較公認(rèn)的致傷因素。Shapior等[11]研究證實(shí)高滲液體可促進(jìn)外周血單核細(xì)胞IL-8 mRNA及蛋白的表達(dá),由于IL-8與脂多糖的協(xié)同作用,使TNF-α的合成增加,高滲刺激的時(shí)間越長(zhǎng),TNF-α的表達(dá)越多。TNF-α可直接激活單核/巨噬細(xì)胞和中性白細(xì)胞,導(dǎo)致超氧陰離子生成增加,引起組織損傷。海水偏堿的性質(zhì)一方面可引起細(xì)胞膜內(nèi)外離子濃度的失衡,另一方面可增強(qiáng)細(xì)胞的損傷反應(yīng),偏堿性環(huán)境下的損傷細(xì)胞更易發(fā)生崩解,使膜磷脂釋放,發(fā)生脂質(zhì)過(guò)氧化反應(yīng);還可使受損的組織形成皂化脂肪或可溶性的堿性蛋白,進(jìn)一步加重組織損傷[12]。目前海水浸泡開(kāi)放性創(chuàng)傷的損傷機(jī)制還存在較大爭(zhēng)議,尚未得出全面而令人信服的結(jié)論。周圍神經(jīng)擠壓傷的原發(fā)損傷為外力所致軸突損傷,而繼發(fā)損傷為級(jí)聯(lián)炎癥反應(yīng)所致,包括血管通透性改變、巨噬細(xì)胞的入侵等[13]。周圍神經(jīng)橫斷傷后,斷端產(chǎn)生大量TNF-α、IL-1β、IFN-γ等致炎因子,參與軸索瓦勒變性[14]。這些細(xì)胞因子在周圍神經(jīng)損傷后的再生過(guò)程中具有重要作用,但炎性反應(yīng)是周圍神經(jīng)損傷重要的發(fā)病機(jī)制,過(guò)度的炎性反應(yīng)可造成組織細(xì)胞廣泛損傷,影響軸突再生。本研究發(fā)現(xiàn)在傷后3d及1周、2周時(shí),C組坐骨神經(jīng)中IL-1β、IL-6 mRNA和蛋白表達(dá)水平均高于B組,而4周時(shí)兩組間比較無(wú)明顯差異。TNF-α與IL-1β、IL-6表達(dá)情況的不同在于傷后2周時(shí)C、B組比較無(wú)明顯差異,可能與TNF-α是其他促炎因子級(jí)聯(lián)反應(yīng)的始動(dòng)因素,可誘發(fā)IL-1、IL-6、IL-8等促炎因子的產(chǎn)生有關(guān)[15]。該結(jié)果表明海水浸泡增加了坐骨神經(jīng)組織IL-1β、IL-6和TNF-α的表達(dá),導(dǎo)致炎癥反應(yīng)加重,且海水浸泡坐骨神經(jīng)損傷后的過(guò)度炎性反應(yīng)主要發(fā)生在傷后2周內(nèi)。
甲潑尼龍屬于人工合成的糖皮質(zhì)激素類藥物,具有抗炎和免疫抑制作用。目前有關(guān)甲潑尼龍對(duì)神經(jīng)損傷修復(fù)作用的研究多集中在急性脊髓損傷方面,而與周圍神經(jīng)損傷有關(guān)的研究相對(duì)較少。郜建飛等[16]觀察了丙戊酸鈉、甲潑尼龍以及兩藥聯(lián)合應(yīng)用對(duì)大鼠坐骨神經(jīng)損傷的修復(fù)作用,結(jié)果顯示兩藥聯(lián)合對(duì)神經(jīng)損傷的修復(fù)效果顯著。姜保國(guó)等[17]觀察了高、中、低劑量甲潑尼龍的神經(jīng)修復(fù)作用,結(jié)果顯示全身使用中、低劑量甲潑尼龍能有效促進(jìn)大鼠周圍神經(jīng)再生,但以使用低劑量為宜,以防并發(fā)感染、精神癥狀等不良反應(yīng)。Nachemson等[18]觀察了甲潑尼龍對(duì)大鼠外周神經(jīng)損傷的修復(fù)作用,結(jié)果發(fā)現(xiàn)傷后12周甲潑尼龍組坐骨神經(jīng)運(yùn)動(dòng)傳導(dǎo)速度明顯高于對(duì)照組,提示甲潑尼龍對(duì)神經(jīng)損傷修復(fù)有促進(jìn)作用。坐骨神經(jīng)功能指數(shù)除了可反映肌力恢復(fù)情況外,還可反映肌肉的協(xié)調(diào)功能,已成為評(píng)估坐骨神經(jīng)功能的重要方法。本研究結(jié)果顯示傷后4周D組坐骨神經(jīng)功能指數(shù)明顯高于C組,提示早期應(yīng)用甲潑尼龍有利于坐骨神經(jīng)功能的恢復(fù)。糖皮質(zhì)激素在周圍神經(jīng)損傷中的作用較為復(fù)雜,有研究發(fā)現(xiàn)地塞米松可抑制免疫球蛋白在周圍神經(jīng)損傷部位的沉積,改善損傷神經(jīng)周圍的微環(huán)境,促進(jìn)神經(jīng)的再生及結(jié)構(gòu)和功能的恢復(fù)[19]。本研究結(jié)果顯示甲潑尼龍可減少海水浸泡坐骨神經(jīng)損傷后IL-1β、IL-6和TNF-α的表達(dá),從而減輕炎癥反應(yīng),提示甲潑尼龍促進(jìn)海水浸泡大鼠坐骨神經(jīng)的再生可能是通過(guò)抑制炎性反應(yīng)起作用的,但其具體機(jī)制及信號(hào)通路尚不清楚,同時(shí)最佳給藥時(shí)間、給藥方式及給藥劑量也需進(jìn)一步探討。
本實(shí)驗(yàn)采用人工海水模擬了天然海水的低溫、高滲、低堿理化性質(zhì),對(duì)海水中含有大量的微生物未予考慮,所以該結(jié)果雖可確定海水理化性質(zhì)對(duì)坐骨神經(jīng)神經(jīng)損傷后功能恢復(fù)及IL-1β、IL-6、TNF-α表達(dá)的影響,并觀察到早期激素的干預(yù)作用,但未能完全展示天然海水浸泡后的變化特點(diǎn),仍有待后續(xù)研究進(jìn)一步探討。
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Influence of seawater immersion on expression of proinflammatory cytokines and intervention effect of methylprednisolone for sciatic nerve injury in rats
WANG Hai-feng, DING Hong-xia, HU Feng, HONG He, LI Ge-wei, FU Lai-xiang, FANG Jian*
Department of Micro-Orthopedics, 105 Hospital of PLA (PLA Clinical College Affiliated to Anhui Medical University), Hefei 230031, China
*< class="emphasis_italic">Corresponding author, E-mail: 13956970650@139.com
, E-mail: 13956970650@139.com
This work was supported by the “Eleventh Five-Year Plan” Medical Science Development Foundation of Nanjing Command (09Z008)
ObjectiveTo explore the mechanism of aggravation of sciatic nerve injury after seawater immersion and the protective effect of methylprednisolone against injury so as to provide an experimental basis for clinical treatment of seawater immersion complicated sciatic nerve injury.MethodsA total of 192 Sprague-Dawley rats were randomly divided into group A (sham injury group), group B (injury control group), group C (seawater immersion + injury group), group D (methylprednisolone treatment group). The model of rat sciatic nerve injury was reproduced by crush injury in groups B, C and D. The sciatic nerves were crushed followed by seawater immersion for 1 hour in groups C and D. Methylprednisolone (20mg/(kg.d)) was injectedviathe tail vein in group D for 2 days. The Sciatic Functional Index (SFI) was used to assess the nerve function on 3rd day and 1, 2 and 4 weeks after injury, and IL-1β, IL-6, TNF-α mRNA and protein expression were determined with RT-PCR or immunohistochemistry.ResultsThe SFI of group A showed no significant change on 3rd day up to 4 weeks after injury. The SFIs in groups B, C and D were gradually increased from 3rd day to 4 weeks after injury. SFI was lower in group C compared with groups B and D (P<0.05). The expressions of IL-1β, IL-6 and TNF-α mRNA in group A were lower on 3rd day and 1, 2 and 4 weeks after injury. The expressions of IL-1β and IL-6 mRNA in groups B, C and D were gradually decreased from 3 days to 4 weeks after injury, and theexpression in group C was significantly higher than that of groups B and D on 3rd day and 1 and 2 weeks (P<0.05). No statistical difference was found in the 4th week among groups B, C and D. The expressions of TNF-α mRNA in groups B, C and D were gradually decreased from 3 days to 2 weeks after injury. The expression of TNF-α mRNA in group C was significantly higher than that of groups B and D on the 3rd day and 1st week (P<0.05). No statistical significant difference was found among groups B, C and D at the 2nd and 4th week. The expression levels of IL-1β, IL-6 and TNF-α protein in group A were from (-) to (+) on 3rd day and 1, 2 and 4 weeks after injury. The expression levels of IL-1β, IL-6 and TNF-α protein in groups B, C and D wereon 3rd days and 1 week after injury, while those of IL-1β and IL-6 protein wereand TNF-α protein (-) to (+) at 2 weeks. The expression levels of IL-1β, IL-6 and TNF-α protein in groups B, C and D were (-) to (+) 4 weeks after injury.ConclusionsSeawater immersion would upregulate the expressions of IL-1β, IL-6 and TNF-α after sciatic nerve injury in rats, and it would cause inflammation and hinder the recovery of nerve function. Methylprednisolone could promote the regeneration of sciatic nerve after seawater immersion in rats, probably by inhibiting the inflammatory reaction.
seawater immersion; sciatic nerve injury; methylprednisolone
R651.3
A
0577-7402(2015)10-0788-06
10.11855/j.issn.0577-7402.2015.10.04
2014-11-25;
2015-08-03)
(責(zé)任編輯:胡全兵)
南京軍區(qū)“十一五”醫(yī)學(xué)科研重點(diǎn)課題(09Z008)
王海峰,醫(yī)學(xué)博士。主要從事周圍神經(jīng)損傷的基礎(chǔ)與臨床研究
230031 合肥 解放軍第105醫(yī)院(安徽醫(yī)科大學(xué)解放軍臨床學(xué)院)顯微骨四科(王海峰、丁宏霞、胡灃、洪鶴、李葛巍、符來(lái)想、方健)
方健,E-mail:13956070650@139.com