林凌,張更,邱榮暉,羅道樞,林清
(福建醫(yī)科大學(xué)基礎(chǔ)醫(yī)學(xué)院人體解剖學(xué)與組織學(xué)胚胎學(xué)系,神經(jīng)生物學(xué)研究中心,福州 350122)
新生期缺氧缺血大鼠腦白質(zhì)損傷及腦內(nèi)Fyn、p-ERK和MBP下調(diào)
林凌,張更,邱榮暉,羅道樞,林清*
(福建醫(yī)科大學(xué)基礎(chǔ)醫(yī)學(xué)院人體解剖學(xué)與組織學(xué)胚胎學(xué)系,神經(jīng)生物學(xué)研究中心,福州 350122)
目的 檢測(cè)新生大鼠缺氧缺血后腦內(nèi)酪氨酸蛋白激酶Fyn、p-ERK及髓鞘堿性蛋白(myelin basic protein, MBP)表達(dá)的變化,探討Fyn-ERK通路在缺氧缺血腦白質(zhì)損傷中的作用。方法 新生3日齡SD大鼠24只,隨機(jī)分為對(duì)照組和缺氧缺血(HⅠ)組。缺氧缺血后4周,應(yīng)用HE染色法觀察腦組織病理學(xué)改變;應(yīng)用免疫熒光染色法和Western blot法觀察Fyn、p-ERK及MBP在大鼠腦內(nèi)的定位定量表達(dá)變化。結(jié)果 HE染色顯示缺氧缺血大鼠出現(xiàn)缺氧缺血腦白質(zhì)損傷病理改變;免疫熒光染色和Western blot檢測(cè)顯示腦內(nèi)Fyn、p-ERK和MBP水平均明顯下調(diào)。結(jié)論 新生期缺氧缺血損傷4周后,可能通過Fyn與p-ERK水平的下調(diào)而使MBP減少,進(jìn)而使少突膠質(zhì)細(xì)胞成熟障礙,引起腦白質(zhì)損傷。
新生期缺氧缺血;Fyn蛋白;髓鞘堿性蛋白;腦白質(zhì)
缺氧缺血腦白質(zhì)損傷(hypoxic-ischemic white matter injury,WMⅠ)是早產(chǎn)兒腦損傷的重要類型,可致患兒出現(xiàn)腦癱、智力低下、視聽障礙等多種后遺癥,給社會(huì)和家庭帶來沉重的負(fù)擔(dān)[1]。缺氧缺血WMⅠ的主要病理改變是髓鞘生成障礙,腦白質(zhì)變稀疏甚至軟化。WMⅠ中髓鞘生成障礙的具體機(jī)制仍未明確,目前依舊是國(guó)內(nèi)外研究的熱點(diǎn)。
Src蛋白酪氨酸激酶(protein tyrosine kinases, PTKs)家族成員共有10 種,具有高度同源性,分別由不同基因編碼,通過調(diào)節(jié)蛋白酪氨酸磷酸化,參與調(diào)節(jié)細(xì)胞增殖、分化、遷移和細(xì)胞形態(tài)的維持[2]。Fyn 是該家族的一員,是細(xì)胞內(nèi)一種非受體型酪氨酸激酶[3]。大量研究表明,F(xiàn)yn信號(hào)通路可通過激活髓鞘堿性蛋白(myelin basic protein, MBP)基因而在髓鞘形成中發(fā)揮不可或缺的作用[4,5]。當(dāng)新生大鼠腦白質(zhì)發(fā)生炎癥后Fyn表達(dá)量降低,髓鞘形成障礙[6]。那么,F(xiàn)yn信號(hào)通路在新生大鼠發(fā)生缺氧缺血損傷中是否發(fā)揮同樣的作用?目前未見文獻(xiàn)報(bào)道。對(duì)這一問題的研究將有助于進(jìn)一步明確缺氧缺血WMⅠ的發(fā)病機(jī)制,具有重要意義。故本研究擬通過結(jié)扎新生3日齡SD大鼠雙側(cè)頸總動(dòng)脈及缺氧法建立缺氧缺血(hypoxia-ischemia, HⅠ)損傷模型,應(yīng)用HE染色法觀察腦組織病理學(xué)改變,采用免疫熒光組織化學(xué)染色法和Western blot法檢測(cè)HⅠ后4周大鼠Fyn、p-ERK及MBP在腦內(nèi)的變化,探討Fyn-ERK 通路在缺氧缺血腦白質(zhì)損傷中的作用。
1 實(shí)驗(yàn)動(dòng)物及試劑
新生3日齡SD大鼠24只,體質(zhì)量8.00~11.00g,雌雄不拘,由福建醫(yī)科大學(xué)實(shí)驗(yàn)動(dòng)物中心提供[SCXK(閩)2012-0001],應(yīng)用隨機(jī)數(shù)字表法隨機(jī)分為對(duì)照組和缺氧缺血HⅠ組。小鼠抗大鼠MBP抗體(美國(guó)abcam公司);兔抗大鼠Fyn抗體(美國(guó)Santa Cruz公司);兔抗大鼠ERK、p-ERK抗體(美國(guó)cst公司);Alexa Fluor488標(biāo)記的山羊抗小鼠ⅠgG;Alexa Fluor555標(biāo)記的山羊抗兔ⅠgG(美國(guó)invitrogen公司);小鼠抗大鼠GAPDH抗體,辣根過氧化物酶標(biāo)記的山羊抗兔ⅠgG、山羊抗大鼠ⅠgG及免疫印跡相關(guān)試劑(碧云天生物技術(shù)研究所) 。
2 缺氧缺血損傷模型制作
參照本實(shí)驗(yàn)室原有方法[7]稍加改進(jìn)。無水乙醚麻醉大鼠,無菌條件下作長(zhǎng)約0.5cm頸腹側(cè)正中切口,分離雙側(cè)頸總動(dòng)脈,以8-0顯微外科手術(shù)縫線完全結(jié)扎雙側(cè)頸總動(dòng)脈后縫合皮膚;術(shù)后在37℃水浴箱內(nèi)放置10min,至體溫和活動(dòng)恢復(fù)正常,返籠飼養(yǎng)。返籠恢復(fù)2h后,將大鼠置于低壓氧倉(cāng)全自動(dòng)控制儀(南京柏曼信息科技服務(wù)中心,XF-XC06-Ⅰ)以8%的氧氣缺氧30min。對(duì)照組大鼠僅分離雙側(cè)頸總動(dòng)脈,不予結(jié)扎及缺氧。
3 組織切片標(biāo)本制備
缺氧缺血后4周分別取對(duì)照組和HⅠ組大鼠各6只,10﹪水合氯醛(3ml/kg)麻醉后,通過左心室插管灌注生理鹽水;待流出清亮液體后續(xù)以4﹪多聚甲醛灌注固定。每組取3只大鼠行石蠟包埋HE染色,另3只行冰凍切片用于免疫熒光染色。
4 免疫熒光染色
對(duì)腦組織進(jìn)行冰凍切片,片厚25μm,行漂片染色。以免疫熒光顯色封閉液室溫封閉2h;傾去封閉液,分別滴加小鼠抗大鼠MBP抗體(1:200)、兔抗大鼠Fyn抗體(1:200)和兔抗大鼠p-ERK抗體(1:200),4℃孵育過夜;用0.01mol/L PBS清洗后,分別滴加Alexa Fluor488標(biāo)記的山羊抗小鼠ⅠgG和AlexaFluor555標(biāo)記的山羊抗兔ⅠgG(1:200),37℃孵育2h;DAPⅠ(1mg/L)染核5min,抗熒光淬滅封片劑封片。激光掃描共聚焦顯微鏡(德國(guó),Leica SP8)下觀察,綠色激發(fā)波長(zhǎng)為488nm,發(fā)射波長(zhǎng)為500~530nm;紅色激發(fā)波長(zhǎng)為543nm,發(fā)射波長(zhǎng)為560~600nm;藍(lán)色激發(fā)波長(zhǎng)為405nm,發(fā)射波長(zhǎng)為420~450nm。陰性對(duì)照組以PBS代替一抗進(jìn)行染色。
5 Western blot檢測(cè)
缺氧缺血后4周分別取對(duì)照組和HⅠ組大鼠各6只,以RⅠPA裂解液提取大鼠腦組織總蛋白,BCA法測(cè)定蛋白濃度。每孔上樣量為50μg蛋白,SDS-PAGE凝膠電泳,濕轉(zhuǎn)于PVDF膜。脫脂奶粉封閉,加入兔抗大鼠Fyn、ERK、p-ERK抗體(1:1000)4℃孵育過夜和辣根過氧化物酶標(biāo)記的山羊抗兔ⅠgG、抗小鼠ⅠgG(1:1000)室溫孵育1h或加入小鼠抗大鼠MBP(1:1000)4℃孵育過夜,辣根過氧化物酶標(biāo)記的山羊抗小鼠ⅠgG(1:1000)室溫孵育1h,清洗后進(jìn)行化學(xué)發(fā)光、顯影和定影,生物分子成像儀(日本,LAS 4000 mini)成像。以GAPDH作為內(nèi)參蛋白。
6 統(tǒng)計(jì)學(xué)分析
用ⅠmageJ 2.1圖像分析系統(tǒng)對(duì)Western blot結(jié)果進(jìn)行光密度分析,以各組目的蛋白條帶光密度值對(duì)內(nèi)參蛋白光密度值計(jì)算相對(duì)比值(均數(shù)±標(biāo)準(zhǔn)差),采用SPSSl9.0統(tǒng)計(jì)軟件對(duì)結(jié)果進(jìn)行分析。以P<0.05時(shí)差異有統(tǒng)計(jì)學(xué)意義。
1 缺氧缺血使腦白質(zhì)纖維排列紊亂
于缺氧缺血后4周取腦組織行HE染色,結(jié)果顯示:對(duì)照組腦白質(zhì)(胼胝體)纖維排列致密、整齊(圖1A),缺氧缺血組腦白質(zhì)纖維排列稀疏、紊亂(圖1B)。
2 缺氧缺血降低腦組織內(nèi)Fyn、p-ERK和MBP水平
免疫熒光染色顯示,缺血缺氧組Fyn免疫反應(yīng)陽性物較相應(yīng)對(duì)照組少(圖2),且在胼胝體部位,F(xiàn)yn表達(dá)于細(xì)胞胞體和突起(圖2A2,圖2B2),而在海馬則表達(dá)于神經(jīng)元胞核(圖2A3,圖2B3)。缺氧缺血組p-ERK表達(dá)量亦較相應(yīng)對(duì)照組下降(圖3),并且p-ERK表達(dá)于胼胝體細(xì)胞突起(圖3A2,圖3B2)和海馬神經(jīng)元胞體(圖3A3,圖3B3)。缺氧缺血組MBP免疫反應(yīng)陽性物較相應(yīng)對(duì)照組減少(圖4);局部放大后可見對(duì)照組腦白質(zhì)MBP免疫反應(yīng)陽產(chǎn)性物排列整齊、致密、突起較長(zhǎng)(圖4A2),而缺氧缺血組MBP免疫反應(yīng)陽性物排列較紊亂、稀疏、突起變短(圖4B2)。
圖1 缺氧缺血腦白質(zhì)病理學(xué)變化的HE染色檢測(cè)。cc,胼胝體;A2和B2分別為A1和B1中方框內(nèi)cc的高倍像;比例尺:A1和B1,100μm;;A2和B2,10μmFig. 1 The pathological changes in hypoxic-ischemic rat brain. The corpus callosum (cc) region was examined using HE staining. A1: Control rat; B1: Hypoxia-ischemic rat; A2and B2 Boxed regions at higher magnification from A1 and B1 respectively. Scale bar: 100μm in A1 and B1; 10μm in A2 and B2
提取各組大鼠腦組織總蛋白,以Western blot檢測(cè)Fyn、ERK、p-ERK及MBP水平。結(jié)果顯示,與對(duì)照組相比,缺氧缺血組Fyn和MBP水平顯著下降、p-ERK與總ERK的比例明顯降低(圖5)。
本研究通過永久性結(jié)扎雙側(cè)頸總動(dòng)脈聯(lián)合缺氧法致使新生大鼠發(fā)生缺氧缺血損傷,應(yīng)用HE染色法觀察腦組織病理學(xué)改變,應(yīng)用免疫熒光組織化學(xué)染色法和Western blot 法觀察Fyn、p-ERK和MBP在腦內(nèi)水平變化。我們發(fā)現(xiàn),在缺氧缺血后4周,腦白質(zhì)纖維變稀疏,F(xiàn)yn、p-ERK及MBP的表達(dá)量均較對(duì)照組明顯減少,并且Fyn在胼胝體與海馬的表達(dá)部位不同。
Fyn在海馬表達(dá)于細(xì)胞核,參與神經(jīng)元的活動(dòng),缺氧缺血后其水平顯著下降,這與廖家萬[8]等的研究結(jié)果相一致。他們認(rèn)為低氧可使大鼠海馬神經(jīng)元Fyn表達(dá)降低。而在胼胝體Fyn主要表達(dá)于細(xì)胞質(zhì)和突起,由于胼胝體主要成分是少突膠質(zhì)細(xì)胞和神經(jīng)元突起,故筆者推測(cè),胼胝體中Fyn可能主要作用于少突膠質(zhì)細(xì)胞,但Fyn在海馬與胼胝體表達(dá)部位不同的具體原因及機(jī)制尚不清楚,有待進(jìn)一步研究證實(shí)。
圖2 免疫熒光檢測(cè)缺氧缺血對(duì)腦組織Fyn水平的影響。cc,胼胝體;HP,海馬;A2和B2,分別為A1和B1中方框內(nèi)CC的高倍像;A3和B3,分別為A1和B1中方框內(nèi)HP的高倍像;比例尺:A1和B1,100μm;A2、A3和B2、B3,25μm。Fig. 2 The effects of hypoxia-ischemia on brain Fyn level. cc, corpus callosum; HP, hippocampus; A2 and B2, the images of cc at higher magnification from A1 and B1, respectively; A3 and B3, the images of HP at higher magnification from A1 and B1, respectively; scale bar: 100μm in A1 and B1; 25μm in A2, A3, B2 and B3
圖3 免疫熒光檢測(cè)缺氧缺血對(duì)腦組織p-ERK水平的影響。cc,胼胝體;HP,海馬;A2和B2,分別為A1和B1中方框內(nèi)CC的高倍像;A3和B3,分別為A1和B1中方框內(nèi)HP的高倍像;比例尺:A1和B1,100μm;A2、A3和B2、B3,25μm。Fig. 3 The effects of hypoxia-ischemia on the brain p-ERK level. cc, corpus callosum; HP, hippocampus; A2 and B2, the high magnification images of cc in A1 and B1; A3 and B3, the high magnification images of HP in A1 and B1; scale bar: 100μm in A1 and B1; 25μm in A2, A3, B2 and B3
圖4 免疫熒光檢測(cè)缺氧缺血對(duì)腦白質(zhì)MBP水平的影響。A2和B2,分別為A1和B1中方框內(nèi)白質(zhì)的高倍像;比例尺:A1和B1,100μm;A2和B2,25μm。Fig.4 The effect of hypoxia-ischemia on MBP level in the white matter of brain; A2 and B2, the high magnification images of the white matter in the frames from A1 and B1; scale bar: 100μm in A1 and B1; 25μm in A2 and B2
圖5 缺血缺氧下調(diào)腦白質(zhì)Fyn、p-ERK、MBP水平。A,F(xiàn)yn、p-ERK、MBP水平代表性Western blot檢測(cè);B,F(xiàn)yn水平的統(tǒng)計(jì)學(xué)分析;C,p-ERK水平的統(tǒng)計(jì)學(xué)分析;D,MBP水平的統(tǒng)計(jì)學(xué)分析; *,與對(duì)照組相比,0.01<P<0.05Fig.5 The effect of hypoxia-ischemia on the Fyn, p-ERK, MBP level of brain white matter. A, levels of Fyn, p-ERK, MBP were determined by western blot; B, statistic analysis for Fyn level; C, statistic analysis for p-ERK level; D, statistic analysis for MBP level; *, 0.01<P< 0.05, compared with the control
由于WMⅠ患兒認(rèn)知和行為學(xué)障礙通常在幼兒期才明顯固定化,而1月齡大鼠在神經(jīng)發(fā)育上相當(dāng)于人類2~5歲幼兒[9]。且研究表明,新生大鼠缺氧缺血后4周可見早期少突膠質(zhì)前體細(xì)胞大量增殖,但新生的早期少突膠質(zhì)前體細(xì)胞雖可向晚期少突膠質(zhì)前體細(xì)胞發(fā)育,卻無法進(jìn)一步分化為成熟少突膠質(zhì)細(xì)胞及產(chǎn)生髓鞘蛋白[10,11]。因此,為明確少突膠質(zhì)細(xì)胞無法分化成熟是否與Fyn相關(guān),本實(shí)驗(yàn)選擇缺氧缺血后4周作為觀測(cè)點(diǎn)。結(jié)果發(fā)現(xiàn),新生大鼠缺氧缺血后4周,腦組織中的Fyn和MBP水平下降,并且組織學(xué)顯示腦白質(zhì)纖維排列疏松,說明Fyn水平下降可能引起髓鞘生成障礙,這與其它報(bào)道大致吻合。已有的研究證實(shí),F(xiàn)yn可誘導(dǎo)少突膠質(zhì)細(xì)胞發(fā)生遷移[12],促進(jìn)少突膠質(zhì)細(xì)胞和施萬細(xì)胞的成熟和發(fā)育[13,14],在中樞神經(jīng)系統(tǒng)髓鞘形成過程中具有不可或缺的作用。Goto等的研究則顯示,F(xiàn)yn基因敲除小鼠與野生型小鼠相比,少突膠質(zhì)細(xì)胞的數(shù)量減少且形態(tài)發(fā)生改變,胼胝體稀疏[15]。Xie等發(fā)現(xiàn),新生大鼠腦白質(zhì)發(fā)生炎癥后Fyn含量降低,髓鞘形成障礙[6]。這些研究共同提示Fyn在髓鞘生成中發(fā)揮重要作用,這有賴于Fyn的特性。Fyn為細(xì)胞內(nèi)非受體型酪氨酸激酶,為Src家族蛋白酪氨酸激酶中的一員,可通過促使酪氨酸磷酸化發(fā)揮作用,酪氨酸激酶磷酸化級(jí)聯(lián)反應(yīng)參與髓鞘形成過程中信號(hào)的傳導(dǎo),其中包括 MAPK/ERK 等信號(hào)傳導(dǎo)通路[16]。因此,本研究進(jìn)一步觀察了ERK的磷酸化水平,結(jié)果顯示缺氧缺血后4周p-ERK的表達(dá)降低,由此我們推測(cè),ERK磷酸化水平下降可能與Fyn水平下調(diào)有關(guān)。
缺氧缺血腦白質(zhì)損傷為早產(chǎn)兒腦損傷的常見類型,主要病理表現(xiàn)為髓鞘合成障礙,腦白質(zhì)變疏松甚至軟化。WMⅠ可致存活患兒出現(xiàn)腦癱、認(rèn)知障礙、視覺異常等嚴(yán)重的神經(jīng)系統(tǒng)后遺癥,其發(fā)病機(jī)制尚未完全明確,至今仍缺乏有效的防治措施。本研究發(fā)現(xiàn)新生大鼠缺氧缺血后,F(xiàn)yn水平下調(diào)、ERK磷酸化水平降低,同時(shí)MBP水平也明顯下調(diào)。由此提示,新生期腦缺氧缺血后可能通過Fyn-ERK通路蛋白的下調(diào)而使MBP水平降低,進(jìn)而使髓鞘生成障礙,少突膠質(zhì)細(xì)胞成熟障礙,最終導(dǎo)致腦白質(zhì)損傷。但缺氧缺血如何誘導(dǎo)Fyn表達(dá)下降有待進(jìn)一步的研究加以證實(shí)。
[1] Munck P, Haataja L, Maunu J, et a1. Cognitive outcome at years of age in Finnish infants with very low birth weight born between 2001 and 2006. Acta Paediatr, 2010, 99(3): 359-366.
[2] Thomas SM, Brugge JS. Cellular functions regulated by Src family kinases. Annu Rev Cell Dev Biol, 1997, 13: 513-609. [3] Colognato H, Ramachandrappa S, Olsen ⅠM, et a1. Ⅰntegrins direct Src family kinases to regulate distinct phases of oligodendrocyte development. J Cell Biol, 2004, 167(2): 365-375.
[4] Sperber, BR, Boyle-Walsh EA, Engleka MJ, et al. A unique role for Fyn in CNS myelination. J Neurosci, 2001, 21(6): 2039-2047.
[5] Umemori H, Kadowaki Y, Hirosawa K, et al. Stimulation of myelin basic protein gene transcription by Fyn tyrosine kinase for myelination. J Neurosci, 1999, 19(4):1393-1397. [6] Xie D, Shen F, He S, et al. ⅠL-1beta induces hypomyelination in the periventricular white matter through inhibition of oligodendrocyte progenitor cell maturation via FYN/MEK/ ERK signaling pathway in septic neonatal rats. Glia, 2016, 64(4): 583-602.
[7] 林凌,張更,林巧梅,等. 新生大鼠缺氧缺血腦白質(zhì)損傷模型學(xué)習(xí)記憶能力的變化.解剖學(xué)報(bào),2016,47(6):738-743.
[8] 廖家萬,鐘敬亮,胡煜輝,等. 低氧對(duì)大鼠海馬神經(jīng)元酪氨酸蛋白激酶Fyn表達(dá)的影響.解剖學(xué)雜志,2011,34(4): 511-513.
[9] Jiang W, Duong TM, de Lanerolle NC. The neuropathology of hyperthermic seizures in the rat. Epilepsia, 1999, 40(1): 5-19.
[10] Back SA, Miller SP. Brain injury in premature neonates: A primary cerebral dysmaturation disorder? Ann Neurol, 2014, 75(4): 469-486.
[11] Buser JR, Maire J, Riddle A, et al. Arrested preoligodendrocyte maturation contributes to myelination failure in premature infants. Ann Neurol, 2012, 71(1): 93-109.
[12] De Avila M, Vassall KA, Smith GS, et al. The proline-rich region of 18.5 kDa myelin basic protein binds to the SH3-domain of Fyn tyrosine kinase with the aid of an upstream segment to form a dynamic complex in vitro. Biosci Rep, 2014, 34(6): 775-788.
[13] Czopka T, Ffrench-Constant C, Lyons DA. Ⅰndividual oligodendrocytes have only a few hours in which to generate new myelin sheaths in vivo. Dev Cell, 2013, 25(6):599-609.
[14] Yamauchi J, Miyamoto Y, Torii T, et al. Phosphorylation of cytohesin-1 by Fyn is required for initiation of myelination and the extent of myelination during development. Sci Signal, 2012, 5(243): 1-15.
[15] Goto J, Tezuka T, Nakazawa T, et al. Loss of Fyn tyrosine kinase on the C57BL/6 genetic background causes hydrocephalus with defects in oligodendrocyte development. Mol Cell Neurosci, 2008, 38(2):203-212.
[16] Haley Peckham, Lauren Giuffrida, Rhiannon Wood, et al. Fyn is an intermediate kinase that BDNF utilizes to promote oligodendrocyte myelination. Glia, 2016, 64(2): 255-269.
Hypoxic-ischemic white matter injury and down-regulation of Fyn, p-ERK and MBP in neonatal rat brain
Lin Ling, Zhang Geng, Qiu Ronghui, Luo Daoshu, Lin Qing*
(Department of Human Anatomy, Histology and Embryology, School of Basic Medical Science, Research Center for Neurobiology, Fujian Medical University, Fuzhou 350122, China)
Objective To understand the role that Fyn-ERK pathway plays in hypoxic-ischemic white matter injury in neonatal rats. Methods 3-day-old new born SD rats were randomly divided into control and hypoxic-ischemic groups. The histology of rat brain tissues 4 weeks after operation was examined using HE staining. The distribution and expression level of Fyn, p-ERK and MBP protein were detected by immunocytochemistry and western blotting. Results The white matter injury was observed in hypoxic-ischemic rats. The levels of Fyn, p-ERK and MBP protein significantly decreased in the brains of hypoxic-ischemic rats, compared to the control group. Conclusion The results suggest that hypoxia-ischemia may decrease MBP level in neonatal rats through downregulating Fyn and p-ERK protein levels, which may lead to oligodendrocyte maturation disorder and white matter injury.
Neonatal hypoxia-ischemia; Fyn protein; myelin basic protein; white matter
R722.6
A DOⅠ:10.16705/ j. cnki. 1004-1850.04.004
2017-04-25
2017-08-02
國(guó)家自然科學(xué)基金青年科學(xué)基金項(xiàng)目(81501305);福建省教育廳重點(diǎn)項(xiàng)目(JA13135)
林凌,女(1982 年),漢族,碩士,實(shí)驗(yàn)師
*通訊作者(To whom correspondence should be addressed):linqing522@126.com
中國(guó)組織化學(xué)與細(xì)胞化學(xué)雜志2017年4期