潘罅,尹友生,李清初,李康慧,韋家智,馬文峰,冷斌
(桂林醫(yī)學(xué)院附屬醫(yī)院,廣西桂林541000)
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雷洛昔芬對(duì)鎘染毒后腎小管上皮細(xì)胞存活情況及1-α羥化酶表達(dá)的影響
潘罅,尹友生,李清初,李康慧,韋家智,馬文峰,冷斌
(桂林醫(yī)學(xué)院附屬醫(yī)院,廣西桂林541000)
目的觀察應(yīng)用雷洛昔芬對(duì)鎘染毒的腎小管上皮細(xì)胞存活情況及1-α羥化酶表達(dá)的影響,探討雷洛昔芬治療鎘中毒導(dǎo)致腎毒性的機(jī)制。方法 分離純化SD大鼠腎小管上皮細(xì)胞原代細(xì)胞。分別用濃度為2.5、5.0、10.0、20.0、40.0 μmol/L的氯化鎘對(duì)腎小管上皮細(xì)胞染毒24 h,采用MTT法測(cè)算腎小管上皮細(xì)胞的相對(duì)存活率。選取20.0 μmol/L的氯化鎘劑量作用于腎小管上皮細(xì)胞,分別用0.05、0.10、0.50、1.00 μmol/L的雷洛昔芬干預(yù)24 h,采用MTT法測(cè)算腎小管上皮細(xì)胞的相對(duì)存活率。將腎小管上皮細(xì)胞分為空白對(duì)照組、氯化鎘組、雷洛昔芬組,空白對(duì)照組培養(yǎng)于DMEM 培養(yǎng)基,氯化鎘組以20.0 μmol/L的氯化鎘染毒腎小管上皮細(xì)胞,雷洛昔芬組以20.0 μmol/L的氯化鎘染毒后給予雷洛昔芬0.10 μmol/L干預(yù),均干預(yù)24 h,在顯微鏡下觀察細(xì)胞形態(tài),采用RT-PCR法檢測(cè)腎小管上皮細(xì)胞1-α羥化酶mRNA表達(dá)。結(jié)果 2.5、5.0、10.0、20.0、40.0 μmol/L的氯化鎘干預(yù)24 h后,腎小管上皮細(xì)胞的相對(duì)存活率均降低(P均<0.01),且氯化鎘濃度較高時(shí)細(xì)胞相對(duì)存活率較低。對(duì)鎘染毒后的腎小管上皮細(xì)胞以0.05、0.10、0.50、1.00 μmol/L的雷洛昔芬干預(yù)24 h后,腎小管上皮細(xì)胞的相對(duì)存活率均高于鎘染毒細(xì)胞(P均<0.01)??瞻讓?duì)照組腎小管上皮細(xì)胞形態(tài)正常,氯化鎘組腎小管上皮細(xì)胞形態(tài)異常、大量細(xì)胞死亡,雷洛昔芬組細(xì)胞形態(tài)異常較氯化鎘組明顯減輕。氯化鎘組腎小管上皮細(xì)胞1-α羥化酶mRNA相對(duì)表達(dá)量低于空白對(duì)照組,雷洛昔芬組1-α羥化酶mRNA相對(duì)表達(dá)量高于氯化鎘組(P均<0.05)。結(jié)論 雷洛昔芬對(duì)氯化鎘染毒的腎小管上皮細(xì)胞具有保護(hù)作用,可上調(diào)鎘染毒后腎小管上皮細(xì)胞1-α羥化酶mRNA的表達(dá)。
腎小管上皮細(xì)胞;雷洛昔芬;氯化鎘;鎘中毒;腎毒性;1-α羥化酶;骨質(zhì)疏松
隨著經(jīng)濟(jì)發(fā)展,環(huán)境污染已成為嚴(yán)重影響人群健康的重要因素,其中重金屬污染導(dǎo)致的疾病備受關(guān)注。上世紀(jì)日本“痛痛病”就是因長(zhǎng)期飲用被硫酸鎘污染的水引起的慢性鎘中毒。腎臟與骨骼是鎘中毒常見(jiàn)的靶器官[1],慢性鎘中毒最主要的臨床表現(xiàn)是導(dǎo)致鈣流失,從而引起骨質(zhì)疏松。目前研究認(rèn)為,鎘中度導(dǎo)致的骨質(zhì)疏松繼發(fā)于腎損傷[2]。雷洛昔芬是一種雌激素受體調(diào)節(jié)劑,臨床常用于骨質(zhì)疏松的治療。1-α羥化酶是調(diào)節(jié)體內(nèi)鈣磷代謝的活性維生素D合成的關(guān)鍵酶。2014年5月~2015年11月,我們以SD大鼠原代腎小管上皮細(xì)胞為研究對(duì)象,觀察雷洛昔芬對(duì)氯化鎘染毒后腎小管上皮細(xì)胞存活情況及1-α羥化酶表達(dá)的影響,探討雷洛昔芬對(duì)鎘中毒后腎毒性的影響。
1.1動(dòng)物與試劑新生(出生不足24 h)SD大鼠10只,購(gòu)于桂林醫(yī)學(xué)院動(dòng)物實(shí)驗(yàn)中心。氯化鎘(國(guó)藥集團(tuán)化學(xué)試劑有限公司);鹽酸雷洛昔芬(大連美侖生物技術(shù)有限公司);DMEM 低糖培養(yǎng)液(美國(guó)Gibco 公司);胎牛血清(美國(guó)Gemini公司);TRIzol 試劑、逆轉(zhuǎn)錄酶試劑盒、2×Taq PCR Master Mix 及 DNA Marker(天根生化科技北京有限公司);引物(美國(guó)Invitrogen 公司);四氮唑藍(lán)(MTT,美國(guó)Amresco 公司);二甲基亞砜(DMSO,美國(guó)Sigma公司);青-鏈霉素混合液(美國(guó)Hyclone 公司);Percoll細(xì)胞分離液(GE公司);Ⅰ型膠原酶(美國(guó)Sigma公司)。
1.2原代腎小管上皮細(xì)胞的提取及培養(yǎng)取新生SD大鼠雙腎,去除包膜及腎蒂,分離剪碎腎皮質(zhì),剪碎至約1 mm大小,轉(zhuǎn)移至濃度為1 g/LⅠ型膠原酶的DMEM溶液中。將得到的細(xì)胞懸液轉(zhuǎn)移至100目不銹鋼網(wǎng)上,過(guò)濾、研磨,網(wǎng)下液體經(jīng)200目篩網(wǎng)過(guò)濾后,離心后棄上清,將細(xì)胞沉淀用含血清的DMEM制成5 mL細(xì)胞懸液。取預(yù)先配好的45% Percoll分離液,將細(xì)胞懸液輕鋪其上,離心后取近管底第2層細(xì)胞懸液,即為近端腎小管節(jié)段及其游離的腎小管上皮細(xì)胞。原代培養(yǎng)5~7 d后,用0.25%胰蛋白酶(含0.02%EDTA)消化,離心后按1∶2分裝接種。第4天可傳第2代。經(jīng)細(xì)胞形態(tài)學(xué)鑒定,細(xì)胞形態(tài)符合腎小管上皮細(xì)胞特點(diǎn)。
1.3氯化鎘對(duì)腎小管上皮細(xì)胞存活的影響觀察
1.3.1鎘染毒將對(duì)數(shù)增長(zhǎng)期的腎小管上皮細(xì)胞以1×105/mL接種于96孔板,每組設(shè)5個(gè)復(fù)孔,37 ℃、5%CO2培養(yǎng)箱中靜置培養(yǎng)24 h。加入20 μL MTT培養(yǎng)4 h后,分別用濃度為2.5、5.0、10.0、20.0、40.0 μmol/L的氯化鎘對(duì)腎小管上皮細(xì)胞染毒24 h??瞻讓?duì)照組用不含氯化鎘的DMEM處理24 h。
1.3.2腎小管上皮細(xì)胞相對(duì)存活率測(cè)算采用MTT法。以上各濃度的氯化鎘染毒后,吸棄孔內(nèi)培養(yǎng)液,加入DMSO 150 μL,避光振蕩10 min,待結(jié)晶充分溶解后,以490 nm波長(zhǎng)測(cè)OD值,計(jì)算細(xì)胞相對(duì)存活率=(OD氯化鎘各濃度/OD空白對(duì)照組)×100%。實(shí)驗(yàn)重復(fù)3次。
1.4雷洛昔芬對(duì)鎘染毒后腎小管上皮細(xì)胞存活的影響觀察根據(jù)1.3.2得到的鎘染毒后細(xì)胞相對(duì)存活率結(jié)果,選用細(xì)胞相對(duì)存活率接近50%的氯化鎘濃度20.0 μmol/L對(duì)腎小管上皮細(xì)胞染毒,然后分別用0.05、0.10、0.50、1.00 μmol/L的雷洛昔芬干預(yù)24 h。采用MTT法測(cè)定腎小管上皮細(xì)胞的相對(duì)存活率。設(shè)立鎘染毒對(duì)照組,將腎小管上皮細(xì)胞以20.0 μmol/L氯化鎘染毒后用DMEM干預(yù)24 h。相對(duì)存活率=(OD雷洛昔芬各濃度/OD鎘染毒對(duì)照組)×100%。
1.5雷洛昔芬對(duì)鎘染毒后腎小管上皮細(xì)胞形態(tài)及1-α羥化酶mRNA表達(dá)的影響觀察
1.5.1細(xì)胞分組及干預(yù)將對(duì)數(shù)生長(zhǎng)期的腎小管上皮細(xì)胞接種于培養(yǎng)皿中,待細(xì)胞貼壁24 h后,分為空白對(duì)照組、氯化鎘組、雷洛昔芬組??瞻讓?duì)照組僅培養(yǎng)于DMEM 培養(yǎng)基;氯化鎘組以20.0 μmol/L的氯化鎘染毒腎小管上皮細(xì)胞;雷洛昔芬組以20.0 μmol/L的氯化鎘染毒后,給予雷洛昔芬0.1 μmol/L干預(yù)。均干預(yù)24 h。
1.5.2腎小管上皮細(xì)胞形態(tài)學(xué)觀察在顯微鏡下觀察細(xì)胞形態(tài)。
1.5.3腎小管上皮細(xì)胞1-α羥化酶mRNA表達(dá)檢測(cè)采用RT-PCR法。培養(yǎng)24 h后收集各組細(xì)胞。細(xì)胞總RNA的提取按TRIzol總RNA提取試劑說(shuō)明書(shū)操作。以 cDNA 為模板進(jìn)行RT-PCR反應(yīng),反應(yīng)體系為20.0 μL。引物由Invitrogen公司合成,序列如下:1-α羥化酶上游5′-ACACACACACACCAATATGT-3′,下游5′-TGGTGCCAGTAAAGTCAGGAA-3′,159 bp;GAPDH 上游5′-ATGGGAAGCTGGTCATCAAC-3′,下游5′-GTGGTTCACACCCATCACAA-3′,221 bp。PCR 反應(yīng)條件:預(yù)變性94 ℃ 3 min,94 ℃ 30 s、61 ℃1 min、72 ℃ 30 s共30個(gè)循環(huán),72 ℃ 5 min。取 PCR 產(chǎn)物行瓊脂糖凝膠電泳,所得電泳灰度圖片用Sensi Ansys 凝膠圖像分析軟件分析,測(cè)量各條帶灰度值(IOD),以1-α羥化酶mRNA IOD 值與GAPDH的比值表示1-α羥化酶mRNA的相對(duì)表達(dá)量。
2.1不同濃度氯化鎘對(duì)腎小管上皮細(xì)胞存活的影響結(jié)果2.5、5.0、10.0、20.0、40.0 μmol/L氯化鎘干預(yù)24 h后,腎小管上皮細(xì)胞的相對(duì)存活率分別為80.136 5%、61.448 1%、57.050 8%、51.819 6%、33.586 1%,均低于空白對(duì)照組(P均<0.01)。
2.2不同濃度雷洛昔芬對(duì)鎘染毒腎小管上皮細(xì)胞存活的影響結(jié)果0.05、0.10、0.50、1.00 μmol/L的雷洛昔芬干預(yù)24 h后,腎小管上皮細(xì)胞的相對(duì)存活率分別為157.110 6%、168.848 8%、140.632 1%、137.923 3%,各濃度雷洛昔芬干預(yù)24 h后腎小管上皮細(xì)胞的相對(duì)存活率均高于鎘染毒對(duì)照組(P均<0.01)。
2.3各組腎小管上皮細(xì)胞形態(tài)學(xué)表現(xiàn)空白對(duì)照組腎小管上皮細(xì)胞形態(tài)正常;氯化鎘組腎小管上皮細(xì)胞與培養(yǎng)皿底貼合不緊密,大部分細(xì)胞形態(tài)異常,大量細(xì)胞死亡;雷洛昔芬組病理改變較氯化鎘組明顯減輕,腎小管上皮細(xì)胞與培養(yǎng)皿底貼合較緊密,較少數(shù)細(xì)胞發(fā)生形態(tài)改變。
2.4各組腎小管上皮細(xì)胞1-α羥化酶mRNA表達(dá)比較 氯化鎘組腎小管上皮細(xì)胞中的1-α羥化酶mRNA相對(duì)表達(dá)量低于空白對(duì)照組,雷洛昔芬組1-α羥化酶mRNA相對(duì)表達(dá)量高于氯化鎘組(P均<0.05)。見(jiàn)圖1、2。
注:A為空白對(duì)照組;B為氯化鎘組;C為雷洛昔芬組。Marker左側(cè)為1-α羥化酶mRNA,右側(cè)為GAPDH。
圖1各組腎小管上皮細(xì)胞1-α羥化酶mRNA表達(dá)情況(RT-PCR法)
圖2 各組腎小管上皮細(xì)胞1-α羥化酶mRNA相對(duì)表達(dá)量
鎘是已知的在生物體內(nèi)最易蓄積的毒物之一,很少量的鎘進(jìn)入體內(nèi)就可因生物蓄積和生物放大作用,對(duì)機(jī)體產(chǎn)生一系列的損傷[3]。鎘可導(dǎo)致機(jī)體急、慢性中毒,急性鎘中毒可引起機(jī)體多種靶器官及組織損傷,慢性鎘中毒可導(dǎo)致腎臟、肝臟、骨骼、神經(jīng)、血液和睪丸等多器官損傷。腎臟是鎘蓄積的最主要靶器官[4]。本研究發(fā)現(xiàn),2.5、5.0、10.0、20.0、40.0 μmol/L的氯化鎘干預(yù)24 h后,腎小管上皮細(xì)胞存活率均低于空白對(duì)照組,且氯化鎘濃度較高時(shí)細(xì)胞存活率較低,提示氯化鎘對(duì)腎小管上皮細(xì)胞具有毒性損傷作用,低濃度的氯化鎘就能使腎小管上皮細(xì)胞的細(xì)胞活力下降。
鎘腎毒性的最初表現(xiàn)通常是腎小管功能障礙[5]。1-α羥化酶主要存在于腎小管上皮細(xì)胞線粒體內(nèi),是活性維生素D31-α羥基化的關(guān)鍵酶[6]。維生素D經(jīng)過(guò)肝細(xì)胞線粒體及近端腎小管上皮細(xì)胞線粒體兩次羥化,形成具有生物活性的1,25-(OH)2D3,活性維生素D作用于維生素D受體(VDR),對(duì)鈣磷平衡、骨代謝、細(xì)胞分化和增殖起著重要的調(diào)節(jié)作用[7]。生理劑量的活性維生素D3能促進(jìn)腸道及腎臟對(duì)鈣離子的吸收,增加骨鈣含量,其缺乏可以導(dǎo)致骨質(zhì)疏松。而雌激素能提高1-α羥化酶的活性[8],進(jìn)而影響活性維生素D3,調(diào)節(jié)體內(nèi)鈣磷代謝。本研究發(fā)現(xiàn),氯化鎘組腎小管上皮細(xì)胞1-α羥化酶mRNA相對(duì)表達(dá)量低于空白對(duì)照組,提示氯化鎘可造成腎小管上皮細(xì)胞1-α羥化酶mRNA表達(dá)降低。
雷洛昔芬是新型的選擇性雌激素受體調(diào)節(jié)劑[9],對(duì)骨組織具有雌激素樣保護(hù)作用,在乳腺和子宮組織中則具有拮抗雌激素作用,常被用于骨質(zhì)疏松的治療,不良反應(yīng)較小[10]。研究表明,雌激素和雷洛昔芬均能有效治療絕經(jīng)后婦女的骨質(zhì)疏松癥[11]。但雷洛昔芬具有不增加乳腺癌發(fā)生率等優(yōu)點(diǎn)。研究發(fā)現(xiàn),雷洛昔芬治療絕經(jīng)后婦女骨質(zhì)疏松的同時(shí),還可以延緩腎功能衰竭并且降低患者病死率,這可能與調(diào)節(jié)雌激素受體參與腎臟保護(hù)功能有關(guān)[12]。本研究發(fā)現(xiàn),0.05、0.10、0.50、1.00 μmol/L的雷洛昔芬干預(yù)鎘染毒細(xì)胞24 h后,腎小管上皮細(xì)胞的存活率均高于鎘染毒對(duì)照組,表明各濃度的雷洛昔芬均可提高鎘染毒腎小管上皮細(xì)胞的存活率、促進(jìn)腎小管上皮細(xì)胞的生長(zhǎng),雷洛昔芬對(duì)于鎘染毒的腎小管上皮細(xì)胞具有保護(hù)作用;細(xì)胞形態(tài)學(xué)觀察發(fā)現(xiàn),空白對(duì)照組腎小管上皮細(xì)胞形態(tài)正常,氯化鎘組腎小管上皮細(xì)胞形態(tài)異常,大量細(xì)胞死亡,而雷洛昔芬組腎小管上皮細(xì)胞病理改變較氯化鎘組明顯減輕,提示鎘染毒對(duì)腎小管上皮細(xì)胞具有毒性損傷作用,而雷洛昔芬對(duì)鎘染毒后腎小管上皮細(xì)胞的毒性損傷具有明顯的保護(hù)作用。本研究發(fā)現(xiàn),雷洛昔芬組1-α羥化酶mRNA相對(duì)表達(dá)量高于氯化鎘組,提示雷洛昔芬可上調(diào)鎘染毒后腎小管上皮細(xì)胞1-α羥化酶mRNA表達(dá),可能是其進(jìn)一步發(fā)揮對(duì)鎘染毒后骨質(zhì)疏松治療作用的機(jī)制之一。
[1] Agneta A.Bone is it the critical organ for cadmium exposure[J]. Toxi Let, 2012, 211(3):1-11.
[2] Nie J, Liu Y, Zeng G, et al. Cadmium accumulation and tolerance of macleaya cordata: a newly potential plant for sustainable phytoremediation in cd-contaminated soil[J]. Environ Sci Pollut Res Int, 2016,23(10): 10189-10199.
[3] Moon CS, Yang HR, Nakatsuka H, et al. Time trend of cadmium intake in Korea[J]. Environ Health Prev Med, 2016, 21(3):118-128.
[4] 田嬌,朱志良. 鎘電池廠職業(yè)性慢性鎘中毒發(fā)病情況分析[J].實(shí)用預(yù)防醫(yī)學(xué),2012,19(1):35-36.
[5] Mortada WI, Hassanien MM, Donia AF, et al. Application of cloud point extraction for cadmium in biological samples of occupationally exposed workers: relation between cadmium exposure and renal lesion[J]. Biol Trace Elem Res, 2015,168(2):303-310.
[6] Somjen D, Knoll E, Sharon O, et al. Calciotrophic hormones and hyperglycemia modulate vitamin D receptor and 25 hydroxyy vitamin D 1-alpha hydroxylase mRNA expression in human vascular smooth muscle cells[J]. J Steroid Biochem Mol Biol, 2015,148:210-213.
[7] Palaniswamy S, Williams D, Jarvelin MR, et al. Vitamin D and the promotion of long-term metabolic health from a programming perspective[J]. Nutr Metab Insights, 2015,8(1):11-21.
[8] 李朦,袁耿彪. 血清25-羥維生素D和雌激素水平與骨密度相關(guān)性的臨床研究[J]. 國(guó)際檢驗(yàn)醫(yī)學(xué)雜志,2013,34(22):3043-3045.
[9] 陳巧紅,葛勤,林綺玲,等. 雷洛昔芬對(duì)絕經(jīng)后骨質(zhì)疏松患者骨代謝及血脂變化的臨床效果[J]. 當(dāng)代醫(yī)學(xué),2011,17(21):139-140.
[10] Naves DM,Carrillo LN, Rodriguez RA. Differential effects of 17 beta-estradiol and raloxifene on bone and lipid metabolism in rats with chronic kidney disease and estrogen insufficiency[J]. Menopause, 2010,17(4):766-771.
[11] Naylor KE, Clowes JA, Finigan J, et al. The effect of cessation of raloxifene treatment on bone turnover in postmenopausal women[J]. Bone, 2010,46(3):592-597.
[12] 尹友生,錢(qián)穆周. 雷洛昔芬對(duì)血液透析婦女骨質(zhì)疏松的干預(yù)作用[J].山東醫(yī)藥,2012,52(12):83-85.
Effect of raloxifene on cell survival and expression of 1-α-hydroxylase in cadmium-induced renal tubular epithelial cells
PANXia,YINYousheng,LIQingchu,LIKanghui,WEIJiazhi,MAWenfeng,LENGBin
(1AffiliatedHospitalofGuilinMedicalUniversity,Guilin541000,China)
ObjectiveTo observe the effect of raloxifene on the cell survival and the expression of 1-α-hydroxylase in renal tubular epithelial cells induced by cadmium chloride, and to invesitage the mechanism of osteoporosis caused by cadmium poisoning. MethodsThe primary renal tubular epithelial cells of SD rats were centrifugated and purified. Using different concentrations (2.5, 5.0, 10.0, 20.0 and 40.0 μmol/L) of cadmium chloride to interfere renal tubular epithelial cells and evaluating the relative survival rate of renal tubular epithelial cells by MTT after 24 h. Using cadmium chloride (20 μmol/L) and different concentrations (0.05, 0.10, 0.50 and 1.00 μmol/L) of raloxifene to interfere the renal tubular epithelial cells and evaluating the survival rate of renal tubular epithelial cells by MTT after 24 h. The renal tubular epithelial cells were divided into the blank control group, cadmium chloride group and raloxifene group. In the blank control group, we used 10 mL DMEM to cultured cells. In the cadmium chloride group, we used 10 mL cadmium chloride (20 μmol/L) to interfere cells. In the raloxifene group, we used 10 mL cadmium chloride (20 μmol/L) and raloxifene (0.1 μmol/L) to interfere cells. The cell morphology was observed and photographed under a microscope after 24 hours. The expression of 1-α-hydroxylase mRNA was detected by using RT-PCR.ResultsThe survival rate of renal tubular epithelial cells was decreased after 24-hour intervention of cadmium chloride (2.5, 5.0, 10.0, 20.0 and 40.0 μmol/L) (allP<0.01), and the survival rate of cells was decreased with the increasing concentrations of cadmium chloride. Using raloxifene (0.05, 0.10, 0.50 and 1.00 μmol/L) to interfere tubular epithelial cells induced by cadmium chloride for 24 h, the survival rate was higher than that of cells induced by cadmium (allP<0.01). The cell morphology of the blank control group was normal, the cell morphology of cadmium chloride group was abnormal and a lot of cells died. Compared with the cadmium chloride group, raloxifene group alleviated. Compared with the blank control group, the expression of 1-α-hydroxylase mRNA of cadmium chloride group was significantly reduced; compared with the cadmium chloride group, the expression of 1-α-hydroxylase mRNA of the raloxifene group was significantly increased (allP<0.05). ConclusionRaloxifene can protect the renal tubular epithelial cells that exposed to cadmium chloride and it can up-regulated the expression of 1-α-hydroxylase mRNA in renal tubular epithelial cells induced by cadmium chloride.
renal tubular epithelial cells; raloxifene; cadmium chloride; cadmium poisoning; renal toxicity; 1-α-hydroxylas; osteoporosis
廣西醫(yī)療衛(wèi)生重點(diǎn)科研課題(重2012011)。
潘罅(1990-),女,在讀碩士研究生,主要研究方向?yàn)槟I臟疾病的基礎(chǔ)及臨床。E-mail: 401187330@qq.com
簡(jiǎn)介:尹友生(1957-),女,教授,碩士研究生導(dǎo)師,研究方向?yàn)槟I臟疾病的基礎(chǔ)及臨床。E-mail: yinyousheng@163.com
10.3969/j.issn.1002-266X.2016.30.002
R155.3
A
1002-266X(2016)30-0005-04
2016-03-09)