雙酚A類似物的雄性生殖毒性研究進(jìn)展

李紅梅,熊憶茗,徐海明,李圓圓,李金波,秦占芬*

雙酚A類似物的雄性生殖毒性研究進(jìn)展

李紅梅1,2,熊憶茗1,2,徐海明3,李圓圓1,2,李金波1,2,秦占芬1,2*

(1.中國(guó)科學(xué)院生態(tài)環(huán)境研究中心,環(huán)境化學(xué)與生態(tài)毒理學(xué)國(guó)家重點(diǎn)實(shí)驗(yàn)室,北京 100085；2.中國(guó)科學(xué)院大學(xué)資源與環(huán)境學(xué)院,北京 100049；3.寧夏醫(yī)科大學(xué)公共衛(wèi)生與管理學(xué)院職業(yè)衛(wèi)生與環(huán)境衛(wèi)生學(xué)系,寧夏 銀川 750004)

聚焦BPA類似物對(duì)雄性動(dòng)物的生殖毒性研究,分析雙酚S、雙酚F、雙酚AF、雙酚B和雙酚E對(duì)哺乳類實(shí)驗(yàn)動(dòng)物睪丸及組織結(jié)構(gòu)、附睪重量及組織學(xué)結(jié)構(gòu)、激素水平、精子參數(shù)等常規(guī)指標(biāo)的影響,考察關(guān)于魚類和兩棲類動(dòng)物的研究.研究發(fā)現(xiàn),不管暴露劑量高低、暴露方式的差異或是動(dòng)物種屬的不同,所有BPA類似物的暴露都顯示陽(yáng)性結(jié)果,這與BPA雄性生殖毒性尚有爭(zhēng)議的事實(shí)形成對(duì)比,暗示這些BPA類似物具有比BPA更明顯的雄性生殖毒性.總體來(lái)看,目前的BPA類似物雄性生殖毒性的數(shù)據(jù)只局限在有限的幾個(gè)實(shí)驗(yàn)室,且實(shí)驗(yàn)的質(zhì)量控制難以評(píng)價(jià).因此,BPA類似物的雄性生殖毒性的數(shù)據(jù)還需要更多實(shí)驗(yàn)室的驗(yàn)證,并且過(guò)程中需要嚴(yán)格控制動(dòng)物實(shí)驗(yàn)的質(zhì)量,以獲得更加可靠且可重復(fù)的結(jié)果.

雙酚A；類似物；雄性；生殖毒性；質(zhì)量控制

雙酚A(BPA)主要用于合成聚碳酸脂、環(huán)氧樹(shù)脂等高分子材料.因其巨大的生產(chǎn)和使用規(guī)模,BPA廣泛存在于各種環(huán)境介質(zhì)和生物體中[2].大量的動(dòng)物實(shí)驗(yàn)顯示,BPA具有內(nèi)分泌干擾等多種毒性效應(yīng)[3-5].一些流行病學(xué)也支持BPA可能與一些疾病的發(fā)生相關(guān)[6].鑒于此,部分國(guó)家/地區(qū)已經(jīng)開(kāi)始逐步限制或禁止BPA在一些產(chǎn)品中的使用.為了應(yīng)對(duì)管制措施,一些BPA類似物,如雙酚S (BPS)、雙酚F (BPF)、雙酚AF (BPAF)、雙酚B (BPB)、雙酚E (BPE)等,部分地作為BPA替代品使用.目前這些 BPA類似物在多種環(huán)境介質(zhì)、食品、消費(fèi)品、血液、尿液和母乳中被廣泛檢出,并呈現(xiàn)出增加趨勢(shì)[8-10].因此,研究人員開(kāi)始關(guān)注BPA替代品的安全性問(wèn)題.

BPA是一種具有雌激素活性和抗雄激素活性的內(nèi)分泌干擾物.一些研究顯示BPA對(duì)生殖系統(tǒng)尤其是雄性生殖靶器官具有一定毒性作用,但是也有很多陰性結(jié)果的報(bào)道BPA是否具有明顯的生殖毒性目前還存在爭(zhēng)議[11].BPA類似物能與雌激素受體(ER)結(jié)合,發(fā)揮雌激素受體激動(dòng)劑的作用[12],能競(jìng)爭(zhēng)性的與雄激素受體AR結(jié)合,表現(xiàn)出抗雄激素效應(yīng)[12]同樣,已有文獻(xiàn)報(bào)道BPS、BPF、BPAF、BPB、BPE這5種BPA類似物有BPA類似的激素活性,可產(chǎn)生內(nèi)分泌干擾效應(yīng),表現(xiàn)出一定的雄性生殖毒性效應(yīng)[13]然而,這些綜述研究的BPA類似物生殖毒性效應(yīng)的文獻(xiàn)信息有限,缺乏一定的系統(tǒng)性.

為了更全面的認(rèn)識(shí)BPA類似物的雄性生殖毒性,本文以BPA類似物(BPA analogues)、雄性(male)、生殖(reproductive)為主題詞,在PubMed、Elsevier SDOL、Springer、SinoMed、CNKI等數(shù)據(jù)庫(kù)中進(jìn)行檢索,篩選了關(guān)于BPA類似物雄性生殖毒性的體內(nèi)研究文獻(xiàn).分析這些物質(zhì)對(duì)哺乳類實(shí)驗(yàn)動(dòng)物(大鼠和小鼠)睪丸及組織結(jié)構(gòu)、附睪重量及組織學(xué)結(jié)構(gòu)、激素水平、精子參數(shù)等幾個(gè)常規(guī)指標(biāo)的影響,同時(shí)考察關(guān)于魚類和兩棲類動(dòng)物的相關(guān)研究,關(guān)注這些研究的質(zhì)量控制情況,以期獲得對(duì)BPA類似物雄性生殖毒性較為全面的認(rèn)識(shí).

1 BPA類似物對(duì)哺乳類實(shí)驗(yàn)動(dòng)物的雄性生殖毒性

文獻(xiàn)報(bào)道BPA類似物對(duì)成年和發(fā)育過(guò)程中鼠的生殖系統(tǒng)可造成一定的損傷,主要表現(xiàn)在睪丸及組織結(jié)構(gòu)、附睪重量及組織學(xué)結(jié)構(gòu)、激素水平、精子參數(shù)等幾個(gè)常規(guī)指標(biāo)的變化.本文共收集到16篇BPA類似物對(duì)鼠雄性生殖毒性的研究文獻(xiàn),其中10篇涉及BPS,6篇涉及BPF,3篇涉及BPAF,5篇涉及BPB,3篇涉及BPE(表1).從睪丸及組織結(jié)構(gòu)、附睪重量及組織學(xué)結(jié)構(gòu)、激素水平、精子參數(shù)等常規(guī)指標(biāo)分析各種BPA類似物對(duì)雄性生殖系統(tǒng)的影響.

表1 BPA類似物暴露對(duì)實(shí)驗(yàn)鼠的雄鼠生殖系統(tǒng)的影響

續(xù)表1

注: GD: 懷孕天數(shù); PND:出生后天數(shù); F3代: 子三代; PD: 受孕后天數(shù); SG: 精原細(xì)胞; Sc: 精母細(xì)胞; St: 精子細(xì)胞; SM: 精子活力; SD: 精子損傷; SC: 精子數(shù)量; SVW: 精囊重量; PW: 前列腺重量; AGD: 肛殖距; NR: 乳頭滯留; T: 睪酮; E2: 雌二醇; FSH: 促卵泡生成素; LH: 黃體生成素; ROS: 活性氧; LPO: 脂質(zhì)過(guò)氧化;SOD:超氧化物歧化酶;顯著上調(diào):“↑”;顯著下調(diào):“↓”;未出現(xiàn)明顯效應(yīng):“—”;未檢測(cè)指標(biāo):“/”;有效應(yīng)“√”;CD-1小鼠與ICR小鼠屬同一品系,表中記錄以原文表述為準(zhǔn).

1.1 BPS對(duì)哺乳類實(shí)驗(yàn)動(dòng)物的雄性生殖毒性

Ullah等[14-15]研究表明,不同劑量的BPS以不同方式的暴露對(duì)不同發(fā)育階段的雄性大鼠、小鼠生殖系統(tǒng)均具有一定的毒性.起初該團(tuán)隊(duì)關(guān)注了較低劑量BPS灌胃暴露(50μg/(kg·d))對(duì)成年雄性成年SD大鼠生殖發(fā)育的影響.他們認(rèn)為BPS盡管對(duì)睪丸重量和生精細(xì)胞沒(méi)有影響,但是可引起附睪管管腔面積減少及輸精管上皮直徑下降等組織形態(tài)學(xué)變化.同時(shí),還可干擾精子發(fā)生過(guò)程,減少精子數(shù)量[14-15].另外2項(xiàng)高劑量研究均顯示50mg/(kg·d)的劑量灌胃成年雄性SD大鼠28d后,可引起睪丸組織形態(tài)學(xué)、精子參數(shù)和激素水平變化,具體表現(xiàn)為生精小管數(shù)量明顯減少、生精小管上皮高度降低、生精小管管腔內(nèi)精子細(xì)胞減少;可損傷精子DNA,損傷生殖軸功能,表現(xiàn)為促卵泡生成素(FSH)、促黃體生成素(LH)及睪酮(T)水平顯著降低.作者同時(shí)發(fā)現(xiàn)BPS下調(diào)抗氧化酶活性(SOD,POD,CAT),上調(diào)活性氧(ROS)和脂質(zhì)過(guò)氧化物水平(LPO),認(rèn)為上述生殖損傷可能是由氧化應(yīng)激引起的[16-17].事實(shí)上,該團(tuán)隊(duì)還報(bào)道了較低劑量BPS(50μg/L),按照每只大鼠平均5mL/(100g·d)的飲水量計(jì)算,折合為2.5mg/(kg·d) BPS長(zhǎng)期暴露可對(duì)生精功能和性激素水平產(chǎn)生影響,抑制剛斷乳雄性SD大鼠的睪丸內(nèi)生精小管的發(fā)育,減少睪丸中精原細(xì)胞、精母細(xì)胞和精子細(xì)胞的數(shù)量,影響精子活力、日精子發(fā)生量和附睪中精子數(shù)量,并導(dǎo)致血漿中FSH、LH及T濃度降低,雌二醇(E2)水平上升[18].該團(tuán)隊(duì)還發(fā)現(xiàn),孕期飲水暴露BPS影響SD大鼠睪丸發(fā)育、精子發(fā)生及性激素合成等.但是實(shí)驗(yàn)子鼠是以個(gè)數(shù)為統(tǒng)計(jì)單元,沒(méi)有按照“窩/籠”統(tǒng)計(jì)[19].在以上的研究中,BPA表現(xiàn)出與BPA類似物一樣的的毒性效應(yīng),對(duì)不同發(fā)育時(shí)期雄鼠的生殖系統(tǒng)產(chǎn)生一定的生殖毒性[16,18-19].

除此之外, Shi等[20]以CD-1小鼠為實(shí)驗(yàn)動(dòng)物研究了BPS暴露對(duì)雄性生殖系統(tǒng)的影響.該團(tuán)隊(duì)首先關(guān)注了BPS暴露新生雄性小鼠所致的生殖毒性.研究者將新生小鼠每隔3d皮下注射BPS(50μg/kg, 10mg/kg)60d后,能引起成年鼠T和E2水平上升.同時(shí),干擾精子發(fā)生過(guò)程,影響精子質(zhì)量.此外,Shi等[21]研究了孕期(GD11～GD21)BPS灌胃暴露(50μg/ (kg·d))對(duì)雄性子代小鼠的生殖毒性.結(jié)果顯示,BPS可引起雄性子代小鼠生精小管和生精細(xì)胞凋亡增加,干擾DNA甲基化以及組蛋白修飾的甲基轉(zhuǎn)移酶的表達(dá).同時(shí),對(duì)凋亡、自噬和氧化應(yīng)激相關(guān)因子的基因表達(dá)水平也有顯著影響.為了進(jìn)一步明確BPS暴露所致的跨代雄性生殖毒性,Shi等[22]探究了孕期(GD7～GD21)BPS暴露(0.5, 50μg/(kg·d))對(duì)F3代雄性子鼠生殖系統(tǒng)的毒性效應(yīng),暴露可影響F3代成年雄鼠精子質(zhì)量,干擾生殖激素的分泌水平,這可能是由于雄鼠睪丸中DNA甲基轉(zhuǎn)移酶(DNMTs)和組蛋白標(biāo)記被破壞后表觀遺傳修飾發(fā)生改變所致.而在這2項(xiàng)孕期實(shí)驗(yàn)中,統(tǒng)計(jì)單元均為鼠的個(gè)數(shù).John等[23]也對(duì)剛出生鼠皮下注射BPS(0.05,10mg/(kg·d)),發(fā)現(xiàn)此化合物也可引起了生精小管的組織學(xué)結(jié)構(gòu)損傷:生精小管直徑、管腔直徑和上皮高度均下降.同樣,在這些研究中,BPA能夠?qū)е虏G丸組織學(xué)發(fā)生改變、生精功能降低及生殖激素紊亂[22-23],BPA發(fā)揮著與BPS類似的生殖毒性.

1.2 BPF對(duì)哺乳類實(shí)驗(yàn)動(dòng)物的雄性生殖毒性

早期研究認(rèn)為,高劑量(500mg/(kg·d))BPF在PND70～PND98灌胃暴露成年大鼠后,導(dǎo)致雄鼠體重降低[24].相似的,Ullah等[25]報(bào)道了50mg/(kg·d) BPF經(jīng)口經(jīng)暴露成年大鼠后,睪丸內(nèi)精子細(xì)胞和生精小管數(shù)量明顯減少,FSH、LH及T水平降低,精子DNA受損.作者將這些效應(yīng)歸因于POD的降低,ROS和LPO的增加.Ullah等[18]還發(fā)現(xiàn)給剛斷乳大鼠通過(guò)飲水暴露5μg/(kg·d) BPF 336d后,生精小管管腔面積、管腔直徑均降低、血漿T、LH和FSH濃度降低、而E2升高;此外,大鼠精原細(xì)胞、精母細(xì)胞和精子細(xì)胞明顯減少.Ullah等[19]認(rèn)為孕期SD大鼠暴露低劑量BPF (5μg/(kg·d))后,大鼠生精小管高度降低、精子活力、日精子發(fā)生量和附睪精子數(shù)均降低,血漿FSH、LH及T濃度降低,E2水平、活性氧和抗氧化物酶活性升高.但是該研究中孕期暴露的子鼠還是以個(gè)體數(shù)為統(tǒng)計(jì)單元.與BPS一樣,部分文獻(xiàn)報(bào)道了各種劑量BPA對(duì)鼠的生殖系統(tǒng)都有一定的毒性效應(yīng)[25].

1.3 BPAF對(duì)哺乳類實(shí)驗(yàn)動(dòng)物的雄性生殖毒性

Feng等[26]發(fā)現(xiàn)通過(guò)灌胃暴露14d后,50mg/(kg·d) BPAF可使成年雄性大鼠血清睪酮水平降低. 200mg/(kg·d) BPAF可使FSH、LH和T水平下降,下調(diào)抑制素B(INHB)、ERα和黃體化激素受體(LHR)的mRNA水平.暴露可導(dǎo)致甾體類基因1450表達(dá)水平降低.作者認(rèn)為,BPAF可以通過(guò)影響垂體性腺軸產(chǎn)生生殖毒性.在Umano等[27]的研究中,30,100mg/(kg·d) BPAF灌胃暴露成年SD大鼠28d后,實(shí)驗(yàn)動(dòng)物動(dòng)情周期發(fā)生改變.高劑量組睪丸間質(zhì)細(xì)胞萎縮、睪丸、附睪、精囊及前列腺重量均下降.Li等[28]結(jié)果顯示,孕期和哺乳期SD母鼠連續(xù)17d灌胃100mg/(kg·d) BPAF后,青春期前雄性子鼠體重顯著降低,血清T水平顯著升高,參與T合成相關(guān)的多種基因(-1,,3-,7, 17-)表達(dá)顯著上調(diào),而顯著下調(diào),導(dǎo)致這些結(jié)果的原因是BPAF對(duì)青春期前雄鼠有一定的促雄激素效應(yīng).目前還沒(méi)有研究報(bào)道低劑量BPAF暴露對(duì)雄鼠生殖系統(tǒng)的影響.

1.4 BPB對(duì)哺乳類實(shí)驗(yàn)動(dòng)物的雄性生殖毒性

高劑量BPB每隔7d腹腔注射1次的急性(2次)和亞急性實(shí)驗(yàn)中(4次),12.5,25,37.5mg/kg BPB可導(dǎo)致青春期(5～6周齡)小鼠精子細(xì)胞DNA損傷,且精子數(shù)量顯著下降、形態(tài)受損及活率下降[29].高劑量BPB灌胃成年大鼠也可使精子數(shù)目減少、生精小管高度下降、精子DNA受損、生殖激素分泌水平紊亂以及氧化應(yīng)激損傷[16-17].Ullah等[18]還認(rèn)為,即使是50μg/(kg·d) BPB飲水暴露同樣導(dǎo)致老年鼠睪丸、附睪及精囊重量下降,生精小管上皮高度降低,生殖細(xì)胞數(shù)量減少,各種生殖軸激素水平降低.與之相似,大鼠孕全期通過(guò)飲水暴露50μg/L BPB,在PND80時(shí),雄性子鼠的睪丸和附睪在組織形態(tài)學(xué)上表現(xiàn)出明顯的改變.同時(shí),暴露可影響E2、T水平及POD活性[19].在這兩項(xiàng)低劑量飲水暴露的實(shí)驗(yàn)中,BPA導(dǎo)致子鼠的睪丸和附睪的組織學(xué)發(fā)生的變化比BPB的效應(yīng)要強(qiáng).對(duì)實(shí)驗(yàn)質(zhì)量控制的分析發(fā)現(xiàn)子鼠依然沒(méi)有以“窩/籠”為統(tǒng)計(jì)單元.

1.5 BPE對(duì)哺乳類實(shí)驗(yàn)動(dòng)物的雄性生殖毒性

Shi等[22]以新生CD-1小鼠為實(shí)驗(yàn)動(dòng)物,皮下注射方式暴露BPE,每隔3d注射1次,劑量為50μg/ (kg·d),在PND60時(shí)可檢測(cè)到精子數(shù)量和活力顯著降低;生殖細(xì)胞發(fā)育的進(jìn)程受到抑制;精子發(fā)生階段分布異常;E2及T水平顯著上調(diào).小鼠在GD11～GD21暴露于BPE (50μg/(kg·d))后,子代小鼠睪丸生精小管和生精細(xì)胞凋亡水平升高,與凋亡、自噬和氧化應(yīng)激相關(guān)的基因表達(dá)受到顯著影響,DNA甲基化和組蛋白修飾的甲基轉(zhuǎn)移酶的表達(dá)水平也有不同程度的改變[20].Shi等[23]還發(fā)現(xiàn),雄鼠在GD7～GD21經(jīng)口灌胃0.5,50μg/(kg·d) BPE,可對(duì)F3代雄性子鼠生精功能產(chǎn)生代際影響,改變生殖激素水平,并引起一系列表觀遺傳學(xué)改變.在這幾項(xiàng)研究中,BPA也表現(xiàn)出陽(yáng)性結(jié)果,尤其是孕期子鼠統(tǒng)計(jì)單元是按照子鼠的個(gè)數(shù).

整體看,以上數(shù)據(jù)來(lái)自少數(shù)有限的幾個(gè)實(shí)驗(yàn)室,顯示不論劑量高低,BPA類似物均對(duì)不同品系實(shí)驗(yàn)鼠睪丸及附睪的質(zhì)量和組織學(xué)結(jié)構(gòu)、附屬腺和外生殖器參數(shù)、精子參數(shù)、性激素水平都有一定的影響.即使孕期短期低劑量暴露也出現(xiàn)了陽(yáng)性結(jié)果.灌胃、飲水和注射的暴露方式都對(duì)雄性生殖產(chǎn)生損傷.甚至有些研究顯示BPA類似物表現(xiàn)出比BPA更強(qiáng)的生殖毒性.這與BPA不具有雄性生殖毒性的結(jié)果是矛盾的.值得注意的是,孕期發(fā)育毒性研究的統(tǒng)計(jì)單位的選取標(biāo)準(zhǔn)是“籠/窩”,但是部分研究均以實(shí)驗(yàn)子鼠個(gè)數(shù)作為統(tǒng)計(jì)單元,未使用“窩/籠”作為統(tǒng)計(jì)單元,這些不嚴(yán)格的質(zhì)量控制可能導(dǎo)致出現(xiàn)一些假陽(yáng)性的結(jié)果.

2 BPA類似物對(duì)雄性水生動(dòng)物生殖發(fā)育的影響

2.1 BPS對(duì)雄性斑馬魚生殖發(fā)育的影響

一些研究發(fā)現(xiàn)BPS會(huì)導(dǎo)致斑馬魚出現(xiàn)一些嚴(yán)重的生殖缺陷,BPS可以引起成年雄性斑馬魚生殖系統(tǒng)功能紊亂.例如,Ji等[30]的研究顯示,成年斑馬魚暴露于0.5, 5, 50μg/L BPS 21d,所有暴露組成魚性腺指數(shù)(GSI)顯著下降,0.5μg/L BPS導(dǎo)致F0代E2濃度顯著升高,50μg/L組T下降.19轉(zhuǎn)錄水平上調(diào),17和17HSD轉(zhuǎn)錄水平下調(diào).連續(xù)暴露BPS導(dǎo)致F1代孵化率下降和畸形率增加.Naderi等[31]將成年斑馬魚暴露于0, 0.1, 1, 10, 100μg/L BPS 75d后,發(fā)現(xiàn)雄性斑馬魚性腺指數(shù)下降,T減少,E2及卵黃蛋白原(VTG)增加,精子數(shù)量減少.BPS還可改變生殖軸基因轉(zhuǎn)錄水平.

2.2 BPF對(duì)雄性斑馬魚生殖發(fā)育的影響

Yang等[32]研究了BPF對(duì)雄性斑馬魚生殖系統(tǒng)的損傷效應(yīng),將4月齡斑馬魚暴露于0.001, 0.01, 0.1, 1mg/L BPF 21d后,1mg/L BPF會(huì)損害雄性斑馬魚睪丸組織學(xué)結(jié)構(gòu);0.1, 1mg/L BPF組雄性斑馬魚的T水平呈濃度依賴性下降,E2水平顯著升高;HPG軸上基因表達(dá)顯著改變. Yang等[33]研究BPF對(duì)斑馬魚性別分化關(guān)鍵階段的影響,將受精后的斑馬魚胚胎暴露于同樣劑量的BPF,暴露持續(xù)60d,結(jié)果顯示,暴露可導(dǎo)致雌魚比例顯著上升;100,1000μg/L BPF可誘導(dǎo)睪丸發(fā)育不完全;T水平降低,E2水平升高,且呈濃度依賴性;表征雄性的性二態(tài)基因119的表達(dá)受到抑制;而表征雌性的性二態(tài)基因2及191表達(dá)水平增加.VTG 是水生動(dòng)物體內(nèi)雌激素活性檢測(cè)經(jīng)常使用的生物指標(biāo).0.1, 1μmol/L BPF暴露7d能夠強(qiáng)烈誘導(dǎo)成年雄性斑馬魚VTG的合成.BPA同樣引起與BPF一樣的效應(yīng).實(shí)驗(yàn)統(tǒng)計(jì)單元沒(méi)有按“缸”,而是以單個(gè)實(shí)驗(yàn)動(dòng)物為標(biāo)準(zhǔn)[34].

2.3 BPAF、BPB對(duì)雄性斑馬魚生殖發(fā)育的影響

與之相似,Shi等[35]發(fā)現(xiàn)斑馬魚從胚胎到成年暴露于5, 25,125μg/L BPAF 140d后,成年雄魚T水平下降,E2水平上升.在子代中,親代暴露于125μg/L BPAF時(shí),才可觀察到子代畸形增加和存活率下降.成年接觸相似濃度的BPAF 28d后導(dǎo)致雄性斑馬魚血漿T水平升高,睪丸出現(xiàn)脫細(xì)胞區(qū).在一項(xiàng)2月齡雄性斑馬魚暴露0.5, 1.0, 1.5mg/L雙酚類化合物21d的研究中,BPAF及BPA劑量依賴地誘導(dǎo)VTG的合成, 并且BPAF的效應(yīng)比BPA更強(qiáng)[36].同樣,BPB對(duì)雄性斑馬魚的生殖功能具有劑量依賴性的損害. Yang等[37]研究了4月齡雄性斑馬魚暴露于濃度為0, 0.001, 0.01, 0.1, 1mg/L的BPB 21d,0.1, 1mg/L BPB導(dǎo)致雄魚睪丸LH及T水平顯著降低,且呈現(xiàn)明顯的劑量依賴性.在高劑量暴露組中,雄魚的T水平與對(duì)照組相比較低,而E2水平在3個(gè)劑量下都較高.在1mg/L暴露組中,暴露BPB的雄性斑馬魚的性腺指數(shù)降低;睪丸在組織學(xué)上出現(xiàn)了損傷,并伴有非細(xì)胞區(qū)的出現(xiàn)以及成熟精子細(xì)胞的減少;同時(shí)113和191基因表達(dá)水平顯著升高,、17和17表達(dá)水平均降低.

2.4 BPAF對(duì)雄性兩棲動(dòng)物生殖發(fā)育的影響

非洲爪蛙()是一種研究雌性化效應(yīng)的典型物種. Cai等[38]研究了BPA類似物對(duì)性腺分化的影響,在半靜態(tài)暴露系統(tǒng)中,將蝌蚪從45/46期暴露于BPAF (1, 10, 100nmol/ L)分別至50期、53期和66期.不同濃度的BPAF在不同發(fā)育期均引起精巢形態(tài)與組織學(xué)的改變.在53期BPAF導(dǎo)致精巢中性節(jié)變小和數(shù)量減少,表現(xiàn)出不連續(xù)和分裂的形態(tài),出現(xiàn)卵巢空腔和生精小管發(fā)育不良,即出現(xiàn)了卵巢形態(tài)特征;在分子水平上,53期BPAF抑制了精巢中雄性高表達(dá)基因的表達(dá).與53期出現(xiàn)的性節(jié)異常對(duì)應(yīng),在66期,BPAF引起長(zhǎng)橢圓形狀的精巢形態(tài)出現(xiàn)異常;導(dǎo)致精巢組織學(xué)結(jié)構(gòu)發(fā)生改變,精巢多處出現(xiàn)空腔以及精原細(xì)胞數(shù)量減少.總之,低濃度BPAF抑制了睪丸的分化和后續(xù)發(fā)育,并有一定程度的雌性化作用.

上述研究均顯示BPA類似物及BPA能損傷雄性水生動(dòng)物的生殖系統(tǒng),但個(gè)別研究的質(zhì)量控制不夠嚴(yán)格,水生動(dòng)物實(shí)驗(yàn)沒(méi)有完全按照以“缸”為統(tǒng)計(jì)單元.這一點(diǎn)在生殖發(fā)育實(shí)驗(yàn)中是無(wú)法接受的.綜合來(lái)看,BPA類似物及BPA確實(shí)對(duì)雄性水生動(dòng)物生殖產(chǎn)生一定的損傷.

3 結(jié)論及展望

BPA類似物能夠?qū)π凼笊诚到y(tǒng),特別是低劑量BPS、BPF、BPB、BPE均對(duì)孕期暴露子鼠生殖系統(tǒng)發(fā)育關(guān)鍵期產(chǎn)生一定的影響.具體表現(xiàn)為, BPA類似物會(huì)導(dǎo)致生殖器官重量下降、肛殖距降低、睪丸臟器系數(shù)降低及動(dòng)情周期延長(zhǎng).在組織病理學(xué)方面,可使生精小管數(shù)量變少、直徑變短、高度變低及管腔面積減小.在生殖功能方面,可引起精子活率降低、精子數(shù)量減少,還可影響生殖激素的合成和分泌.同樣,BPA類似物體內(nèi)暴露也對(duì)雄性斑馬魚的生殖系統(tǒng)具有劑量依賴性的損害,可損傷睪丸功能;升高雌雄性別比例;導(dǎo)致GSI下降;干擾激素功能;減少精子數(shù)量.除此之外,BPA類似物還可改變生殖軸基因轉(zhuǎn)錄水平.最后,BPAF可導(dǎo)致發(fā)育中的雄性非洲爪蛙一定程度的雌性化.

在一些研究中,BPA的暴露都給出了陽(yáng)性的結(jié)果,這與目前BPA具有雄性生殖毒性尚有爭(zhēng)議的事實(shí)形成了對(duì)比.關(guān)于BPA類似物對(duì)哺乳類雄性生殖毒性的研究比較少,且僅僅來(lái)自于有限的幾個(gè)研究團(tuán)隊(duì).通過(guò)對(duì)發(fā)育期特別是孕期暴露實(shí)驗(yàn)質(zhì)量控制的評(píng)價(jià)發(fā)現(xiàn),這些研究的動(dòng)物統(tǒng)計(jì)單元存在一定的缺陷,同時(shí),其它大部分的實(shí)驗(yàn)質(zhì)量控制難以評(píng)價(jià).水生動(dòng)物的雄性生殖毒性的實(shí)驗(yàn)質(zhì)量控制評(píng)價(jià)也存在同樣的問(wèn)題, BPA類似物能夠?qū)π坌陨持笜?biāo)產(chǎn)生的毒性效應(yīng)一定程度取決于在相同實(shí)驗(yàn)條件下的質(zhì)量控制差異.因?yàn)殡y以評(píng)估大部分實(shí)驗(yàn)質(zhì)量控制,所以對(duì)很多實(shí)驗(yàn)結(jié)果持謹(jǐn)慎態(tài)度,傾向于BPA類似物確實(shí)對(duì)雄性生殖系統(tǒng)有一定毒性,但是否低劑量的暴露同樣能引起明顯的毒性效應(yīng)還需要進(jìn)一步驗(yàn)證.為了更好的闡明BPA類似物對(duì)發(fā)育期雄性生殖系統(tǒng)的影響,體內(nèi)實(shí)驗(yàn)應(yīng)當(dāng)嚴(yán)格執(zhí)行質(zhì)量控制規(guī)范.此外,盡管目前發(fā)現(xiàn)暴露時(shí)期與毒性效應(yīng)沒(méi)有必然的聯(lián)系,但在生殖與發(fā)育過(guò)程中孕期及哺乳期是發(fā)育的關(guān)鍵期,因此,在以后的研究中應(yīng)當(dāng)著力開(kāi)發(fā)更為敏感的檢測(cè)指標(biāo),同時(shí)也要模擬真實(shí)環(huán)境的聯(lián)合暴露.

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Research progress in male reproductive toxicity of bisphenol A analogues.

LI Hong-mei1,2, XIONG Yi-ming1,2, XU Hai-ming3, LI Yuan-yuan1,2, LI Jin-bo1,2, QIN Zhan-fen1,2*

(1.State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China；2.College of Resources and Environmeal University of Chinese Academy of Sciences, Beijing 100049；3.Department of Occupational and Environmental Hygiene, School of Public Health and Management, Ningxia Medical University, Yinchuan 750004, China)., 2021,41(6)：2939～2945

This paper examined studies on bisphenol analogues and male reproductive toxicity with the focus on analyzing the data involving toxic effects of bisphenol analogues on the testis and organization structure, weight and histological structure of epididymis, hormone levels and sperm parameters in mammals, and investigating several essays about fish and amphibian animal research. All BPA analogues had reproductive hazards in these animals regardless of dose, mode of exposure, or species of animals, which suggested that these BPA analogues had more significant male reproductive toxicity than that of BPA on which researches were still debating. However, the majority of data points on the male reproductive toxicity of BPA analogues was limited from a few laboratories and quality control was also hard to discern. Therefore, to obtain more reliable and repeatable results, the findings on male reproductive toxicity of BPA analogues need to be verified by more laboratories, and the quality of animal experiments should be strictly controlled.

bisphenol A；analogues；male；reproductive toxicity；quality control

X171.5,R114

A

1000-6923(2021)06-2939-07

2020-10-09

國(guó)家重點(diǎn)研發(fā)計(jì)劃(2018YFA0901103);國(guó)家自然科學(xué)基金資助項(xiàng)目(21876196)

* 責(zé)任作者, 研究員, qinzhanfen@rcees.ac.cn

李紅梅(1984-),女,寧夏銀川人,中國(guó)科學(xué)院大學(xué)博士研究生,主要從事內(nèi)分泌干擾生殖毒性研究.發(fā)表論文1篇.