生态毒理学报Asian Journal of Ecotoxicology第18卷第4期2023年8月V ol.18,No.4Aug.2023㊀㊀基金项目:福建省自然科学基金资助项目(2020J01426);宁德师范学院中青年科研项目(2022ZQ101);宁德师范学院科技特派员科研资助专项(2022ZQ401)㊀㊀第一作者:李进寿(1965 ),男,教授,研究方向为生态毒理学,E -mail:***************㊀㊀*通信作者(Corresponding author ),E -mail:***************DOI:10.7524/AJE.1673-5897.20221012001李进寿,陈懿娜,何亮银,等.丁草胺暴露对雄性褐菖鮋精细胞发育的干扰[J].生态毒理学报,2023,18(4):450-458Li J S,Chen Y N,He L Y ,et al.Exposure to butachlor disrupts development of sperm in male Sebastiscus marmoratus [J].Asian Journal of Ecotoxicolo -gy,2023,18(4):450-458(in Chinese)丁草胺暴露对雄性褐菖鮋精细胞发育的干扰李进寿1,2,3,*,陈懿娜1,4,何亮银1,2,3,郭团玉1,5,罗芬1,2,3,阮峻峰1,2,3,周逢芳1,2,31.宁德师范学院生命科学学院,宁德3521002.闽东水产品精深加工福建省高校工程研究中心,宁德3521003.国家海洋局海西海洋特色生物种质资源及生物制品开发公共服务平台,宁德3521004.福建省古田县松吉初级中学,古田3522005.厦门海洋职业技术学院,厦门361100收稿日期:2022-10-12㊀㊀录用日期:2022-12-12摘要:丁草胺是全球范围内使用最广泛的酰胺类除草剂之一㊂目前丁草胺对非目标生物的潜在毒性研究较多,但有关丁草胺对近海鱼类生殖毒性的研究鲜有报道㊂以近海鱼类褐菖鮋为研究对象,探讨丁草胺对海洋鱼类精细胞发育的影响及机制㊂以环境浓度(2㊁20和200ng ㊃L -1)的丁草胺对雄性褐菖鮋暴露50d 后,其精巢成熟精细胞数量下降,发育早期阶段的精原细胞与精母细胞数量上升,精巢雄激素睾酮(T)水平下降,Caspase -3活性上升,γ-谷酰胺转移酶(γ-GT)活性下降㊂相对荧光定量PCR 分析结果显示,促卵泡激素受体基因(FSHR β)与促黄体生成激素受体基因(LHR β)mRNA 表达量被抑制㊂这表明,丁草胺对雄性褐菖鮋有明显的生殖毒性,精巢支持细胞功能被抑制引起睾酮水平降低,进而导致精子发生被抑制㊂精巢细胞凋亡也是原因之一㊂关键词:丁草胺;褐菖鮋;生殖毒性;细胞凋亡;精细胞文章编号:1673-5897(2023)4-450-09㊀㊀中图分类号:X171.5㊀㊀文献标识码:AExposure to Butachlor Disrupts Development of Sperm in Male Sebastiscus marmoratusLi Jinshou 1,2,3,*,Chen Yina 1,4,He Liangyin 1,2,3,Guo Tuanyu 1,5,Luo Fen 1,2,3,Ruan Junfeng 1,2,3,Zhou Fengfang 1,2,31.College of Life Science,Ningde Normal University,Ningde 352100,China2.Engineering Research Center of Mindong Aquatic Product Deep -Processing,Ningde 352100,China3.Administration Hercynian Special Biological Germplasm Resources and Biological Product Development Public Service Platform,Ningde 352100,China4.Gutian Songji Junior High School of Fujian,Gutian 352200,China5.Xiamen Ocean V ocational and Technical College,Xiamen 361100,ChinaReceived 12October 2022㊀㊀accepted 12December 2022第4期李进寿等:丁草胺暴露对雄性褐菖鮋精细胞发育的干扰451㊀Abstract:Butachlor is one of the most widely used amide herbicides in the world.There are many studies on the possible toxic effects of butachlor on non-target organisms,but few studies addressing the reproductive toxicity of butachlor on offshore fishes are available.The present study was conducted to investigate the effects of butachlor on sperm development in Sebastiscus marmoratus and to gain insight into its mechanism.After exposed to buta-chlor at environmental concentrations(2,20,200ng㊃L-1)for50d,the development of sperm in testis was re-pressed in different extent,testosterone(T)was decreased in the testis,while the activities of Caspase-3were dose-dependently increased,and the activities ofγ-GT were dose-dependently decreased.Real-time PCR showed that the expression of FSHRβand LHβwere reduced in the testis.These results indicate that butachlor can cause significant reproductive toxicity to fish.The inhibited expression of FSHRβand LHRβresulted in decreased T levels in the testis and suppressed spermatogenesis.In addition,the apoptosis of testicular cells was another reason for the inhi-bition of spermatogenesis.Keywords:butachlor;S ebastiscus marmoratus;reproductive toxicity;apoptosis;spermatocysts㊀㊀随着现代农业科技的发展,人工合成的杀虫剂已成为最常见的污染源之一[1]㊂20世纪80年代有机氯及有机磷等高毒性农药被逐步淘汰后,三唑类㊁除虫聚酯类与酰胺类等人工合成的相对毒性较低的农药被大量使用㊂其中,酰胺类是亚洲使用最广泛的除草剂[2],仅在我国每年消耗量即在8000t以上[3],且使用量呈逐年攀升的趋势㊂这些药物在使用过程中除了少量作用于靶生物外,更多的药物残留通过农田废水污染了河流与湖泊等淡水水域,且通过江河等汇集于近海海域㊂例如,Mamun等[4]的报道显示在日本一些地区地表水丁草胺(butachlor)的浓度达到0.1~1.4μg㊃L-1,欧美国家的调查也显示,包括甲草胺㊁乙草胺㊁丁草胺及乙丙甲草胺在内的多种酰胺类检出浓度达0.022~3.68μg㊃L-1[5-8],在中国,华北地区与淮河水域地表水中乙草胺的最高检出浓度分别为1.64μg㊃L-1与2.0μg㊃L-1[9-10]㊂而酰胺类除草剂对近海水域的污染方面,黄群腾[11] 2007年在我国福建省九龙江口及厦门近海海水检测到乙草胺㊁丁草胺及异丙甲草胺等多种酰胺类的物质,其中丁草胺浓度达到16.7~104.9ng㊃L-1㊂丁草胺是目前国内农田使用最广泛的三大除草剂之一[3],广泛用在作物出苗前或出苗后早期阶段以防治各种有害杂草[12],仅在在亚洲每年的使用量就达到4500t[13]㊂有关丁草胺对水生生物的毒副作用,已有报道显示对蚯蚓(Eisenia fetida)[14]㊁水蚤(Daphnia carinata)[15]㊁姬蛙(Microhyla)蝌蚪[16]㊁泽蛙(Fejervarya limnocharis)[17]等土壤与水生动物均存在毒性㊂对鱼类,乙草胺可导致泥鳅(Misgurnus an-guillicaudatus)血红细胞的变异[18],斑马鱼(Danio re-rio)胚胎以4~20mmol㊃L-1浓度梯度的丁草胺暴露84h后,胚胎孵化过程受到阻碍且出现畸形和死亡,胚胎雌激素应答基因(Vtg1)表达被显著诱导[19],斑马鱼在25㊁50和100μg㊃L-1浓度的丁草胺中暴露30d后,其繁殖力出现降低,雄性性体比(GSI)指数在50μg㊃L-1和100μg㊃L-1浓度组显著下降,雌性斑马鱼在100μg㊃L-1浓度组血浆睾酮(T)和17-雌二醇(E2)水平出现显著下降[20],Ateeq等[21]的研究则显示丁草胺可引起雄性鲶鱼(Clarias batrachus)精巢小叶支持细胞出现大量凋亡而降低繁殖力㊂以上有关丁草胺对鱼类的毒性研究主要针对的是淡水鱼类,但未见对近海鱼类毒性研究㊂由于丁草胺等酰胺类除草剂在土壤㊁地下水与地表水体均被检测到,且在近海海域有较严重的污染,因此该类农药对近海鱼类的毒性研究具有重要的现实意义㊂本实验参照黄腾群[11]对九龙江口及厦门近海水体环境浓度的检测结果,设置2㊁20㊁200ng L-1浓度梯度的丁草胺对我国东南沿海常见的经济鱼类褐菖鮋(Sebastiscus marm-oratus)进行50d的慢性水体暴露,以调查该类除草剂对海洋鱼类的生殖毒性㊂本研究对除草剂等人工合成的农药在使用过程中对水环境造成的生态风险的评估以及规范使用相关农药具有一定意义㊂1㊀材料与方法(Materials and methods)1.1㊀药品丁草胺(标准品,纯度ȡ95%,产品货号: B114549),购自上海泽叶生物科技有限公司㊂1.2㊀褐菖鮋的驯化和暴露处理及样品的收集试验用鱼参照李进寿等[22]的方法进行驯化和暴露㊂驯化实验:褐菖鮋为霞浦县溪南镇七星村海域购得的海捕鱼,雄鱼大小规格(67.62ʃ3.58)g;驯化期452㊀生态毒理学报第18卷间每天定时定量投喂饵料,且定期观察摄食情况及水质变化;驯化前将砂滤海水用预先经过24h曝气的淡水将盐度调整为22~24,驯化时间7d㊂暴露实验:暴露实验以乙腈溶剂对照组㊁低浓度2ng㊃L-1组㊁中浓度20ng㊃L-1组和高浓度200ng㊃L-1组的浓度梯度分4缸进行,200ng㊃L-1㊁20ng㊃L-1和2ng㊃L-1的药物组分别加入200μL预先用乙腈为溶剂配制的60.00㊁6.00㊁0.60ng㊃μL-1的丁草胺应用液,对照组加入等量体积(200μL)的乙腈溶剂,并立即将缸内实验水体混匀㊂暴露实验过程每天在大致相同的时间将暴露用实验海水更换1/2(30L),同时补充1/2剂量的丁草胺药物㊂大约在每天换水前2h,按照褐菖鮋体质量2%~3%的比例投喂鱼配合饲料,换水过程用虹吸管清除水缸底部的鱼粪和未摄食的饲料残饵㊂实验过程中每隔7d将水缸清洗干净且全部更换暴露用水及丁草胺药物,暴露实验时间为50d㊂暴露实验期间需要利用增氧设备对各缸水体进行不间断充气以保证实验水体的供氧充足㊂暴露实验结束进行采样,用于生化指标测定的试验样品置于-20ħ的冰柜中备用;分子实验的样品放在-80ħ超低温冰箱保存等待检测;用于组织学观察的褐菖鮋精巢组织以饱和的三硝基苯酚溶液固定保存于4ħ冰箱,并在隔夜后更换新的三硝基苯酚固定液㊂杀鱼取样时对各暴露组所有鱼的精巢㊁肝脏和体质量进行称量,以检测各暴露组性体比指数(GSI)和肝体比指数(HSI)㊂1.3㊀组织学分析将饱和三硝基苯酚固定的褐菖鮋精巢经流水清洗过夜后以梯度浓度的乙醇㊁正丁醇进行脱水㊁透明与透蜡处理后以石蜡包埋方式制作切片,在切片机上以4μm厚度切片㊂切片采用苏木精和伊红(H.E.)染色后,镜检对照组及各暴露组精细胞的发育状况㊂脱水步骤:以V(正丁醇)ʒV(无水乙醇)ʒV(水) =20ʒ50ʒ30的溶剂处理2h;以V(正丁醇)ʒV(无水乙醇)ʒV(水)=45ʒ45ʒ10的溶剂处理2h;以V (正丁醇)ʒV(无水乙醇)=75ʒ25的溶剂处理2h;以V(正丁醇)ʒV(无水乙醇)=85ʒ15的溶剂处理1 h;以V(正丁醇)ʒV(无水乙醇)=95ʒ5的溶剂处理1h;以正丁醇处理1h,正丁醇处理1h,正丁醇处理1h(共处理3次)㊂透明:正丁醇和石蜡各半的混合液处理30min㊂透蜡:石蜡Ⅰ透蜡1h,石蜡Ⅱ透蜡1h㊂1.4㊀精巢半胱氨酸蛋白酶-3(Caspase-3)活性的测定褐菖鮋精巢组织先进行匀浆处理,以事先经过预冷且pH调整为7.4的磷酸缓冲液为匀浆液,匀浆后在4ħ条件下以2000r∙min-1速度离心5min 后取精巢组织上清液用于测定Caspase-3活性㊂Caspase-3活性用Caspase试剂盒(Keygene Biotech Co.,Ltd.,中国南京)按照说明书提供的方法测定㊂暴露组样品Caspase-3活性均需调整为等蛋白浓度后与对照组比较分析㊂样品蛋白质浓度以Brad-ford[23]的方法测定,蛋白测定时以牛血清蛋白为标准㊂1.5㊀精巢γ-谷酰胺转移酶(γ-GT)活性的测定γ-GT活性测定时精巢组织的处理同Caspase-3活性测定的方法,γ-GT活性按照γ-GT试剂盒(Key-gene Biotech Co.,Ltd.,中国南京)说明书的方法进行测定㊂γ-GT的单位为U∙g-1,试验条件下15min 产生1μmol的底物定义为1个酶活单位㊂1.6㊀精巢雄性激素睾酮(T)水平的测定睾酮(T)水平以Sun等[24]的方法测定㊂测定前每个精巢组织以m(精巢)ʒm(乙醇)=1ʒ9的比例在冰浴条件下匀浆㊂匀浆后的样品在-80ħ超低温至少保存24h,再用3mL的乙酸乙酯萃取3次㊂萃取物置入5mL离心管内,用在氮吹仪下吹干后加入0.5mL缓冲液㊂T水平的测定采用放射性免疫方法使用试剂盒按照使用说明书测定(北京福瑞生物工程公司)㊂T检测限为0.1~30nmol㊃L-1;批间极差12‰㊂1.7㊀相对定量PCR(real-time PCR)的分析褐菖鮋精巢总RNA用试剂盒提取,cDNA亦用试剂盒反转录㊂总RNA的浓度与纯度的测定用Nanodrop ND-1000分光光度计测定,CYP-19s基因的cDNA片段以笔者此前的方法[22]扩增㊂褐菖鮋靶基因CYP-19s㊁FSHRβ与LHRβ的cDNA片段采用Sun等[25]的方法进行扩增㊂基因mRNA表达的测定也采用Sun等[25]的方法㊂基因相对表达量计算软件(REST-MCS®-version2)用于靶基因mRNA 相对表达量的计算㊂靶基因CYP-19a引物序列为F:5 -GCAGTGCGTGTTGGAGATG-3 ,R:5 -CT-GCTGCGACAGGTTGTTG-3 ;CYP-19b引物序列F:5 -GCTGAGGATAGTGGAGGAGATG-3 ,R:5 -GACCGATGTTGAGAATGATGTT-3 ;FSHRβ引物序列F:5 -TGGTTGTCATGGCAGCAGTG-3 ,R: 5 -GTGGTGTCGATGAATTGGGTT-3 ;LHRβ引物序列F:5 -AGAAGGAGGGCTGTTCCAAGT-3 ,第4期李进寿等:丁草胺暴露对雄性褐菖鮋精细胞发育的干扰453㊀5 -ATGATGCTGTTGTAGGTGGT -3 ㊂1.8㊀数据处理实验结果以SPSS11.0软件进行单因素方差分析(ANOV A),若P <0.05则为显著性差异,各组数据以平均值ʃ标准偏差(mean ʃSD)表达㊂2㊀结果(Results )2.1㊀性体比(GSI)㊁肝体比(HSI)变化如图1所示,褐菖鮋在丁草胺各个浓度暴露组与对照组间GSI 与HSI 均未观察到显著性差异(P >0.05)㊂2.2㊀褐菖鮋精巢细胞发育的组织学切片观察雄性褐菖鮋经过不同浓度的丁草胺暴露50d后的精巢细胞发育的组织学变化如图2所示,从图2中可以观察到随着药物浓度的升高,精巢成熟精子(SP)数量呈减少趋势㊂同时从组织学切片可以观察到精巢由不同的精巢小叶,每个小叶内含有处于不同发育阶段的精细胞,包括在发育早期阶段的精原细胞(SG)㊁精母细胞(SC)以及成熟精子㊂每个暴露组随机取3个不同的精巢分析统计各期生殖细胞的平均百分比,结果显示各暴露组SG 与SC 占比与对照组相比出现上升,其中SG 在中浓度的20ng ㊃L -1组与高浓度的200ng ㊃L -1出现显著性升高,而SC 在各个浓度组均出现显著性升高,而SP 的占比则较对照组出现下降,其中20ng ㊃L -1组与200ng ㊃L -1组精巢中SP 比例显著低于对照组(图3)㊂2.3㊀褐菖鮋精巢雄性激素睾酮(T)的变化如图4所示,褐菖鮋在丁草胺暴露50d 后,各浓度暴露组的雄性激素睾酮(T)水平呈现丁草胺浓度依赖式的下降趋势,且全部显著低于对照组(P<0.05)㊂2.4㊀褐菖鮋精巢Caspase -3活性的变化经过丁草胺暴露50d 后褐菖鮋精巢Caspase -3的活性变化如图5所示,精巢Caspase -3活性变化与丁草胺呈浓度依赖性增强趋势,其中的20ng ㊃L -1组和200ng ㊃L -1组均较对照组出现显著性增强(P<0.05),但2ng ㊃L -1组Caspase -3活性升高不显著(P >0.05)㊂2.5㊀褐菖鮋精巢γ-GT 活性的变化如图6所示,褐菖鮋经丁草胺暴露50d 后,其精巢γ-GT 活性与丁草胺浓度呈负相关性变化趋势,其中200ng ㊃L -1组γ-GTP 活性显著低于对照组(P<0.05)㊂2.6㊀褐菖鮋精巢相关基因表达量的变化如图7所示,褐菖鮋在丁草胺暴露50d 后,其精巢芳香化酶基因(CYP -19a ㊁CYP -19b )㊁促卵泡激素受体基因(FSHR β)与促黄体生成激素受体基因(LHR β)mRNA 表达量均表现出对丁草胺的浓度依赖性下降趋势,其中CYP -19a 基因表达量在中浓度的20ng ㊃L -1组和高浓度的200ng ㊃L -1组均出现显著性下降(P <0.05);CYP -19b 基因的表达量在低浓度的2ng ㊃L -1组与中浓度的20ng ㊃L -1组下降不显著(P >0.05),高浓度的200ng ㊃L -1组表达量有显著性下图1㊀雄性褐菖鮋在丁草胺暴露50d 后性体比(GSI )和肝体比(HSI )的变化注:数据用平均值ʃ标准偏差(means ʃSD)表达(n =25);实验数据用单因素方差分析和Duncan 分析检验,不同字母表示差异显著P <0.05,相同字母表示差异不显著P >0.05㊂Fig.1㊀The gonadosomatic index (GSI)and hepatopancreas somatic index (HSI )changes of maleS.marmoratus in butachlor exposure for 50dNote:Data are presented as means ʃSD (n =25);means of exposures not sharing a common letter are significantly different at P <0.05,and sharing a common letter are not different at P >0.05,as assessed by One -way ANOV A followed by the Dunnett s test.454㊀生态毒理学报第18卷图2㊀丁草胺暴露50d后雄性褐菖鮋精巢的组织学变化切片图注:(a)对照,(b)2ng㊃L-1,(c)20ng㊃L-1,(d)200ng㊃L-1;标尺为50μm;SG为精原细胞,SC为精母细胞,SP为成熟精子细胞㊂Fig.2㊀Histological changes of the testes stained with hematoxylin and eosin in male S.marmoratus exposed to butachlor for50dNote:(a)Control;(b)2ng㊃L-1;(c)20ng㊃L-1;(d)200ng㊃L-1;Bar=50μm;SC,spermatocytes;SG,spermatogonia;SP,sperm.图3㊀雄性褐菖鮋经过丁草胺暴露50d后各阶段精细胞百分比的变化注:SG为精原细胞,SC为精母细胞,SP为成熟精子细胞;数据用平均值ʃ标准偏差(meansʃSD)表达(n=3);实验数据用单因素方差分析和Duncan分析检验,不同字母表示差异显著P<0.05,相同字母表示差异不显著P>0.05㊂Fig.3㊀Percentage of spermatocysts at different stages of development in male S.marmoratus exposed to butachlor for50d Note:SG,spermatogonia;SC,spermatocytes;SP,sperm;the data are expressed as meansʃSD(n=3);means of exposures notsharing a common letter are significantly different at P<0.05,and sharing a common letter are not different at P>0.05,as assessed by One-way ANOV A followed by the Dunnett stest.图4㊀雄性褐菖鮋经丁草胺暴露50d后精巢雄性激素睾酮(T)的变化注:实验数据用平均值ʃ标准偏差(meansʃSD)表示(n=6);组间多重数据比较采用单因素方差分析和Duncan分析检验,不同字母表示差异显著P<0.05,相同字母表示差异不显著P>0.05㊂Fig.4㊀The content of testosterone(T)in the testis of male S.marmoratus exposed to butachlor for50dNote:Data are presented as meanʃSD(n=6);means ofexposures not sharing a common letter aresignificantly different at P<0.05,and sharing a commonletter are not different at P>0.05,as assessedby One-way ANOV A followed by the Dunnett s test.第4期李进寿等:丁草胺暴露对雄性褐菖鮋精细胞发育的干扰455㊀图5㊀雄性褐菖鮋在丁草胺暴露50d 后精巢Caspase-3活性的变化注:实验数据用平均值ʃ标准偏差(means ʃSD)表示(n =5~6);组间多重数据比较采用单因素方差分析和Duncan 分析检验,不同字母表示差异显著P <0.05,相同字母表示差异不显著P >0.05㊂Fig.5㊀Caspase -3activities in the testis of male S.marmoratusexposed to butachlor for 50dNote:Data are presented as mean ʃSD (n =5~6);means of exposures not sharing a common letter are significantly different at P <0.05,and sharing a common letter are not different at P >0.05,as assessedby One -way ANOV A followed by the Dunnett stest.图6㊀丁草胺暴露50d 后雄性褐菖鮋精巢γ-GT 的活性变化注:实验数据用平均值ʃ标准偏差(means ʃSD)表示(n =6);组间数据比较采用单因素方差分析和Duncan 分析检验,不同字母表示差异显著P <0.05,相同字母表示差异不显著P >0.05㊂Fig.6㊀γ-GT activities in the testis of maleS.marmoratus exposed to butachlor for 50dNote:Data are presented as mean ʃSD (n =6);means of exposures notsharing a common letter are significantly different at P <0.05,and sharing a common letter are not different at P >0.05,as assessedby One -way ANOV A followed by the Dunnett s test.降(P<0.05);FSHR β基因的表达量在高浓度的200ng ㊃L -1组显著性下降;LHR β基因的表达量在中浓度的20ng ㊃L -1组与高浓度的200ng ㊃L -1组均显著性下降(P <0.05)㊂3㊀讨论(Discussion )在鱼类生殖毒性的研究中,人工合成的除草剂[26]㊁杀虫剂[22,27]等农药是热点之一,这些报道均表明这些低毒性农药对近海鱼类具有明显的生殖毒性㊂而酰胺类农药对淡水水域水生生物的毒性也已有诸多报道㊂He 等[15]报道丁草胺对斜生栅藻(Scenedesmus obliquus )的96h -EC 50为2.31mg ㊃L -1,对隆线蚤(Daphnia carinata )的48h -EC 50为3.40mg ㊃L -1,显示丁草胺对这2种浮游生物均具有中等毒性㊂在鱼类中,Xiang 等[28]报道以1㊁2㊁5㊁10㊁15μmol ㊃L -1浓度梯度的丁草胺对斑马鱼(Danio rerio )暴露72h 后,其胚胎死亡率和畸形率均出现升高,且与丁草胺呈剂量依赖性上升趋势㊂Chang 等[20]报道雌性斑马鱼在25㊁50和100μg ㊃L -1浓度的丁草胺暴露30d 后,HSI 无显著变化,雄鱼GSI 在50μg ㊃L -1和100μg ㊃L -1浓度组出现显著性下降,雌雄鱼血浆睾酮(T)㊁17-雌二醇(E2)㊁血浆甲状腺素(T4)和三碘甲状腺原氨酸(T3)水平及VTG 水平等出现不同程度的上升或下降㊂这些报道均表明丁草胺对斑马鱼具有明显的生殖毒性,并可导致内分泌系统的紊乱㊂然而,有关酰胺类除草剂对近海鱼类的生殖毒性却未见报道,因此开展酰胺类除草剂对近海鱼类的潜在毒性研究具有现实的意义㊂在本实验中,尽管丁草胺暴露未导致褐菖鮋GSI 与HSI 出现显著性变化,但组织学观察的结果表明丁草胺的暴露引起雄性褐菖鮋性腺精细胞的发育被抑制,体现为成熟精子(SP)数量大量减少,而处于发育早期的精原细胞(SG)与精母细胞(SC)却显著增加㊂环境毒物对鱼类GSI 的影响方面,或许与水域盐度相关㊂Chang 等[20]报道雄性斑马鱼在25㊁50和100μg ㊃L -1的丁草胺中暴露30d 后,GSI 在50μg ㊃L -1和100μg ㊃L -1浓度组出现显著性下降的现象㊂Forsgren 等[29]的报道也指以0.1μg ㊃L -1与1.5μg ㊃L -1浓度的联苯菊酯对雄性虹鳟鱼(Oncorhyn -chus mykiss )进行水体暴露14d 后其GSI 无显著变化,但雌性虹鳟鱼GSI 则有显著性下降㊂鱼类精巢由数量极多的精巢小叶组成,其壁上的支持细胞是支持精子发育的营养通路,因此支持细胞在精子发育过程中起到关键作用[30]㊂而在鱼类精巢的发育过456㊀生态毒理学报第18卷程中,γ-谷酰胺转移酶(γ-GT)对维持支持细胞的活性具有重要作用,因此γ-GT 活性是检验支持细胞功能的重要标记物[30-31]㊂在本研究中,褐菖鮋精巢γ-GT 活性的下降说明丁草胺的暴露导致精巢支持细胞功能降低,研究中FSHR β㊁LHR β基因表达量的下降也证明精巢支持细胞功能降低,因为FSH 激素与LH 激素在精巢支持细胞的增殖过程中均起到决定性的作用[32]㊂图7㊀雄性褐菖鮋在丁草胺暴露50d 后精巢相关基因mRNA 表达量的变化注:基因的相对表达量以β-actin 为内参;实验数据用平均值ʃ标准偏差(means ʃSD)表示(n =4~6);组间多重数据比较采用单因素方差分析实验数据用单因素方差分析和Duncan 分析检验,不同字母表示差异显著P <0.05,相同字母表示差异不显著P >0.05㊂Fig.7㊀Relative mRNA expression of related gene of the testis in male S.marmoratus exposed to butachlor for 50dNote:Values were normalized against β-actin;the data are presented as mean ʃSD (n =6);means of exposures not sharing acommon letter are significantly different at P <0.05,and sharing a common letter are not different at P >0.05,as assessed by One -way ANOV A followed by the Dunnett s test.㊀㊀在动物机体内,为维持体内环境的稳定,不同组织的细胞凋亡是普遍现象,涉及到组织的修复与重塑等过程[33-35]㊂在此过程中,Caspase 家族酶在激活细胞凋亡通道方面担负主要功能,其中Caspase -3是最关键的酶之一[36]㊂本实验结果显示,褐菖鮋在丁草胺暴露后精巢中Caspase -3活性增强,这表明丁草胺的暴露加剧褐菖鮋睾丸精细胞的凋亡㊂已有研究表明环境毒物如重金属镉[37]㊁壬基酚(nonylphenol)与槲皮素(quercetin)等[38]诱导引起的细胞凋亡都可成为影响性腺发育的重要原因,因为这会引起大量精细胞在发育早期出现凋亡,必然导致成熟精子数量大量减少,精巢组织学分析结果也证明了这一点㊂在本研究中,丁草胺的暴露导致了褐菖鮋精巢细胞色素P450芳香化酶(CYP -19s )基因的表达被抑制,这是因为环境有毒物质会影响CYP -19s 基因表达量的变化[39]㊂硬骨鱼类下丘脑-垂体-性腺轴(hypo -thalamic -pituitary -gonadal axis,HPG)是调节性腺发育的主要内分泌系统[26-27],而环境毒性物质可通过抑制脑垂体FSH β与LH β基因的表达[40-41],从而减少FSH 激素与LH 激素的分泌㊂FSH 激素与LH 激素,在雄性鱼类中对精巢小叶维持支持细胞的功能具有重要作用[42],精巢小叶支持细胞功能的下降导致精细胞发育受阻是引起成熟精子数量减少的内在机制㊂研究中褐菖鮋精巢FSHR β与LHR β表达受到抑制而引起精巢睾酮分泌减少,而睾酮含量的下降是精细胞发育被抑制的原因之一,因为鱼类性腺性激素水平在调节性腺发育的过程起重要作用[24]㊂综上所述,丁草胺的暴露引起精巢中γ-GT 活性下降,说明支持细胞受到损伤,进而导致精巢FSHR β与LHR β表达下调,导致睾酮水平下降,抑制了精子发生㊂Caspase -3活性增强促使精巢细胞发生凋亡,是导致成熟精子数量大量减少的另一个原因㊂第4期李进寿等:丁草胺暴露对雄性褐菖鮋精细胞发育的干扰457㊀参考文献(References):[1]㊀程艳红,葛婧,胡高洁,等.3种酰胺类除草剂对斑马鱼不同生长阶段的急性毒性效应[J].生态毒理学报, 2017,12(6):171-178Cheng Y H,Ge J,Hu G J,et al.Acute toxicity effects ofthree amide herbicides to different life stages of zebrafish(Danio rerio)[J].Asian Journal of Ecotoxicology,2017, 12(6):171-178(in Chinese)[2]㊀Kumari N,Narayan O P,Rai L C.Understanding buta-chlor toxicity in Aulosira fertilissima using physiological,biochemical and proteomic approaches[J].Chemosphere, 2009,77(11):1501-1507[3]㊀Yu Y L,Chen Y X,Luo Y M,et al.Rapid degradation ofbutachlor in wheat rhizosphere soil[J].Chemosphere, 2003,50(6):771-774[4]㊀Mamun M I R,Park J H,Choi J H,et al.Developmentand validation of a multiresidue method for determinationof82pesticides in water using GC[J].Journal of Separa-tion Science,2009,32(4):559-574[5]㊀Planas C,Caixach J,Santos F,et al.Occurrence of pesti-cides in Spanish surface waters.Analysis by high resolu-tion gas chromatography coupled to mass spectrometry[J].Chemosphere,1997,34(11):2393-2406[6]㊀Davis D.Washington State Pesticide Monitoring Program:1997surface water sampling report[R].Pullman,WA:Washington State Department of Ecology,1998:16 [7]㊀Griffini O,Bao M L,Barbieri C,et al.Occurrence of pes-ticides in the Arno River and in potable water A surveyof the period1992-1995[J].Bulletin of EnvironmentalContamination and Toxicology,1997,59(2):202-209 [8]㊀Cerejeira M J,Viana P,Batista S,et al.Pesticides in Por-tuguese surface and ground waters[J].Water Research, 2003,37(5):1055-1063[9]㊀任晋,黄翠玲,赵国栋,等.固相萃取-高效液相色谱-质谱联机在线分析水中痕量除草剂[J].分析化学,2001, 29(8):876-880Ren J,Huang C L,Zhao G D,et al.Determination of her-bicides in drinking water by solid phase extraction-liquidchromatography-mass spectrometry[J].Chinese Journalof Analytieal Chemistry,2001,29(8):876-880(in Chi-nese)[10]㊀王子健,吕怡兵,王毅,等.淮河水体取代苯类污染及其生态风险[J].环境科学学报,2002,22(3):300-304Wang Z J,Lv Y B,Wang Y,et al.Assessing the ecologi-cal risk of substituted benzenes in Huaihe River,China[J].Acta Scientiae Circumstantiae,2002,22(3):300-304(in Chinese)[11]㊀黄群腾.水环境中36种农药残留的同时分析方法及其应用[D].厦门:厦门大学,2008:70-71Huang Q T.Simultaneously determination method for36pesticides in aquatic environment and its application[D].Xiamen:Xiamen University,2008:70-71(in Chinese) [12]㊀Mohanty S R,Bharati K,Moorthy B T S,et al.Effect ofthe herbicide butachlor on methane emission and ebulli-tion flux from a direct-seeded flooded rice field[J].Biolo-gy and Fertility of Soils,2001,33(3):175-180[13]㊀Abigail M E A,Samuel S M,Ramalingam C.Addressingthe environmental impacts of butachlor and the availableremediation strategies:A systematic review[J].Interna-tional Journal of Environmental Science and Technology,2015,12(12):4025-4036[14]㊀Chen C,Wang Y H,Zhao X P,et parative andcombined acute toxicity of butachlor,imidacloprid andchlorpyrifos on earthworm,Eisenia fetida[J].Chemo-sphere,2014,100:111-115[15]㊀He H Z,Yu J,Chen G K,et al.Acute toxicity of buta-chlor and atrazine to freshwater green alga Scenedesmusobliquus and cladoceran Daphnia carinata[J].Ecotoxicol-ogy and Environmental Safety,2012,80:91-96[16]㊀Geng B R,Yao D,Xue Q Q.Acute toxicity of the pesti-cide dichlorvos and the herbicide butachlor to tadpoles offour anuran species[J].Bulletin of Environmental Con-tamination and Toxicology,2005,75(2):343-349 [17]㊀Liu W Y,Wang C Y,Wang T S,et al.Impacts of the her-bicide butachlor on the larvae of a paddy field breedingfrog(Fejervarya limnocharis)in subtropical Taiwan[J].Ecotoxicology,2011,20(2):377-384[18]㊀张彬彬,傅荣恕.乙草胺对生物的急性毒理研究[J].滨州医学院学报,2008,31(1):36-37,39Zhang B B,Fu R S.Toxicity of acetochlor on loach[J].Journal of Binzhou Medical University,2008,31(1):36-37,39(in Chinese)[19]㊀Tu W Q,Niu L L,Liu W P,et al.Embryonic exposure tobutachlor in zebrafish(Danio rerio):Endocrine disruption,developmental toxicity and immunotoxicity[J].Ecotoxi-cology and Environmental Safety,2013,89:189-195 [20]㊀Chang J H,Liu S Y,Zhou S L,et al.Effects of butachloron reproduction and hormone levels in adult zebrafish(Danio rerio)[J].Experimental and Toxicologic Patholo-gy:Official Journal of the Gesellschaft Fur Toxikolo-gische Pathologie,2013,65(1-2):205-209[21]㊀Ateeq B,Farah M A,Ahmad W.Evidence of apoptoticeffects of2,4-D and butachlor on walking catfish,Clariasbatrachus,by transmission electron microscopy and DNAdegradation studies[J].Life Sciences,2006,78(9):977-986458㊀生态毒理学报第18卷[22]㊀李进寿,罗芬,阮少江,等.联苯菊酯暴露对雌性褐菖鲉卵巢发育的影响及其毒性机制[J].生态毒理学报, 2016,11(6):323-329Li J S,Luo F,Ruan S J,et al.Bifenthrin exposure disruptsthe development of ovary in female Sebastiscus marmora-tus and the mechanism involved[J].Asian Journal of Ec-otoxicology,2016,11(6):323-329(in Chinese)[23]㊀Bradford M M.A rapid and sensitive method for thequantitation of microgram quantities of protein utilizingthe principle of protein-dye binding[J].Analytical Bio-chemistry,1976,72:248-254[24]㊀Sun L B,Zhang J L,Zuo Z H,et al.Influence of triphe-nyltin exposure on the hypothalamus-pituitary-gonad axisin male Sebastiscus marmoratus[J].Aquatic Toxicology, 2011,104(3-4):263-269[25]㊀Sun L B,Zuo Z H,Luo H M,et al.Chronic exposure tophenanthrene influences the spermatogenesis of male Se-bastiscus marmoratus:U-shaped effects and the reason forthem[J].Environmental Science&Technology,2011,45(23):10212-10218[26]㊀Li J S,Sun L B,Zuo Z H,et al.Exposure to pa-clobutrazol disrupts spermatogenesis in male Sebastiscusmarmoratus[J].Aquatic Toxicology,2012,122-123:120-124[27]㊀Li J S,Luo F,Liu L Y,et al.Exposure to bifenthrin dis-rupts the development of testis in male Sebastiscus marm-oratus[J].Acta Oceanologica Sinica,2017,36(2):57-61 [28]㊀Xiang Q Q,Xu B F,Ding Y L,et al.Oxidative stress re-sponse induced by butachlor in zebrafish embryo/larvae:The protective effect of vitamin C[J].Bulletin of Envi-ronmental Contamination and Toxicology,2018,100(2): 208-215[29]㊀Forsgren K L,Riar N,Schlenk D.The effects of the pyre-throid insecticide,bifenthrin,on steroid hormone levelsand gonadal development of steelhead(Oncorhynchusmykiss)under hypersaline conditions[J].General andComparative Endocrinology,2013,186:101-107[30]㊀Jégou B.The Sertoli cell in vivo and in vitro[J].Cell Bi-ology and Toxicology,1992,8(3):49-54[31]㊀Rasmussen T H,Teh S J,Bjerregaard P,et al.Anti-estro-gen prevents xenoestrogen-induced testicular pathology ofeelpout(Zoarces viviparus)[J].Aquatic Toxicology,2005, 72(3):177-194[32]㊀Sharpe R M,McKinnell C,Kivlin C,et al.Proliferationand functional maturation of Sertoli cells,and their rele-vance to disorders of testis function in adulthood[J].Re-production,2003,125(6):769-784[33]㊀Schwartzman R A,Cidlowski J A.Apoptosis:The bio-chemistry and molecular biology of programmed celldeath[J].Endocrine Reviews,1993,14(2):133-151 [34]㊀Steller H.Mechanisms and genes of cellular suicide[J].Science,1995,267(5203):1445-1449[35]㊀孙琦,范咏梅,赖柯华,等.呋虫胺对斑马鱼胚胎-幼鱼生长发育及细胞凋亡的影响[J].生态毒理学报,2016,11(3):356-364Sun Q,Fan Y M,Lai K H,et al.Effects of dinotefuran onthe embryonic and larvae development and apoptosis inzebrafish(Danio rerio)[J].Asian Journal of Ecotoxicolo-gy,2016,11(3):356-364(in Chinese)[36]㊀Cohen G M.Caspases:The executioners of apoptosis[J].The Biochemical Journal,1997,326(Pt1):1-16[37]㊀Migliarini B,Campisi A M,Maradonna F,et al.Effects ofcadmium exposure on testis apoptosis in the marine tele-ost Gobius niger[J].General and Comparative Endocri-nology,2005,142(1-2):241-247[38]㊀Weber L P,Kiparissis Y,Hwang G S,et al.Increased cel-lular apoptosis after chronic aqueous exposure to nonyl-phenol and quercetin in adult medaka(Oryzias latipes)[J].Comparative Biochemistry and Physiology Toxicology&Pharmacology,2002,131(1):51-59[39]㊀Patel M R,Scheffler B E,Wang L,et al.Effects of benzo(a)pyrene exposure on killifish(Fundulus heteroclitus)ar-omatase activities and mRNA[J].Aquatic Toxicology,2006,77(3):267-278[40]㊀Wu Y S,He Z,Zhang L H,et al.Ontogeny of immunore-active LH and Fsh cells in relation to early ovarian differ-entiation and development in protogynous hermaphroditicricefield eel Monopterus albus[J].Biology of Reproduc-tion,2012,86(3):93[41]㊀Shimizu A,Hamaguchi M,Ito H,et al.Appearances andchronological changes of mummichog Fundulus heterocli-tus FSH cells and LH cells during ontogeny,sexual differ-entiation,and gonadal development[J].General and Com-parative Endocrinology,2008,156(2):312-322[42]㊀Miranda L A,Strüssmann C A,Somoza G M.Effects oflight and temperature conditions on the expression of Gn-RH and GtH genes and levels of plasma steroids in Odon-testhes bonariensis females[J].Fish Physiology and Bio-chemistry,2009,35(1):101-108Ң。