大鼠孕期及哺乳期邻苯二甲酸二(2-乙基己基)酯暴露致雄性仔鼠脑组织病理学改变

目的观察邻苯二甲酸二(2-乙基已基)酯(DEHP)宫内及哺乳期暴露对子代雄性大鼠脑组织发育的影响。方法采用围生期毒性试验的研究方法,将清洁级SD大鼠随机分为阴性对照组(玉米油)和4个DEHP染毒组(125、250、500、1000mg/kg),采用宫内及哺乳期经口灌胃的方式染毒。记录比较孕鼠孕0、20d(GD0、GD20)、仔鼠出生后21d(PND21)母鼠体重及体重增长量、雄性仔鼠不同发育阶段体重、脑脏器系数;观察雄性仔鼠不同发育阶段脑组织病理学及超微病理学改变。结果母鼠染毒期间,体重及体重增长量不同程度降低(P0.05)。不同发育阶段雄性仔鼠体重显示,0～500mg/kg组随染毒剂量增加而增加,1000mg/kg组体重均明显低于相同发育阶段对照组仔鼠体重,仅PND21仔鼠体重500mg/kg组与对照组比较,差异有统计学意义(P0.05)。PND21雄性仔鼠500mg/kg组脑脏器系数低于对照组,1000mg/kg组高于对照组,差异有统计学意义(P0.05)。各发育阶段海马区锥体细胞和大脑皮质神经元细胞表现为不同程度的核固缩变性,500、1000mg/kg组表现较为严重。电镜结果显示各发育阶段海马区锥体细胞核不同程度固缩、线粒体灶性损伤,粗面内质网不同程度损伤,突触增多。结论 DEHP宫内及孕期暴露可引起雄性仔鼠脑组织病理形态改变,可影响雄性仔鼠脑组织生长。     

妊娠期邻苯二甲酸(2-乙基己基)酯暴露对成年后子代雄鼠精子的致突变作用

目的探讨妊娠期邻苯二甲酸(2-乙基己基)酯(DEHP)暴露对成年后子代大鼠精子的致突变作用。方法将32只健康SPF级SD孕鼠随机分为4组,分别为对照(玉米油)组和2、10、50 mg/kg DEHP染毒组,每组8只。自GD13至GD19,采用灌胃方式进行,每天1次。每窝随机选取1只初生雄性仔鼠,观察其生殖器的发育情况;于70日龄时,观察精子的畸形情况。结果妊娠期DEHP暴露雄性仔鼠的体重、肛殖距系数(AGI)及主要生殖器(睾丸、附睾、精囊腺)的脏器系数与对照组比较,差异无统计学意义(P0.05);主要生殖器未见畸形。2 mg/kg及50 mg/kg DEHP染毒组子代雄性大鼠精子的头部畸形率和总畸形率均高于对照组,差异有统计学意义(P0.05);而各剂量DEHP染毒组子代雄性大鼠的尾部畸形率与对照组比较,差异均无统计学意义(P0.05)。结论在本实验条件下,妊娠期较低(2 mg/kg)及较高(50 mg/kg)剂量DEHP暴露对子代雄鼠的精子均具有遗传毒性作用。     

邻苯二甲酸(2-乙基己基)酯低剂量暴露对雄性小鼠生殖发育的影响

目的观察邻苯二甲酸(2-乙基己基)酯(DEHP)低剂量暴露对雄性小鼠的生殖发育毒性作用。方法将清洁级ICR小鼠随机分为4个DEHP染毒组(1/120LD50,1/60LD50,1/30LD50,1/15LD50,即250、500、1000、2000mg/kg组),阳性对照组(环磷酰胺,40mg/kg)和阴性对照组(玉米油);DEHP染毒组和阴性对照组灌胃染毒30d,阳性对照组灌胃5d,每天1次。采用一般生殖毒性试验和显性致死突变试验的方法,研究DEHP低剂量暴露对雄性小鼠生殖细胞的损伤作用和生育能力的影响。结果一般生殖毒性试验结果显示,低剂量DEHP染毒雄性小鼠睾丸、附睾重量降低(r睾丸=-0.578,P<0.01;r附睾=-0.661,P<0.01),精子总数减少(r=-0.608,P<0.01),精子畸形率增高(r=0.836,P<0.01),精子活动度降低(P<0.05)。显性致死突变试验研究结果显示,250mg/kgDEHP染毒组小鼠受孕率降低,但与阴性对照组比较,差异无统计学意义(P>0.05);DEHP染毒组子代小鼠平均着床数减少(r=-0.892,P<0.01),与阴性对照组比较,差异均具有统计学意义(P<0.01);平均早期死亡胚胎数随染毒剂量增加而增加(r=0.996,P<0.01),250mg/kg染毒组与阴性对照组比较,差异无统计学意义(P>0.05)。结论DEHP低剂量暴露对雄性小鼠具有生殖毒性作用,可降低小鼠受孕率,使子代小鼠平均着床数减少,平均早期死亡胚胎数增加。     

哺乳期小鼠阿特拉津染毒对仔鼠精子存活率的影响

为研究哺乳期小鼠阿特拉津染毒对仔鼠精子存活率的影响,将16窝健康清洁级昆明小鼠[16只母鼠及其生后7d雄性仔鼠(每窝5～7只)]随机分为4组,分别为对照组(植物油)和低(50mg/kg)、中(100mg/kg)、高(200mg/kg)剂量阿特拉津染毒组,每组4窝。对母鼠进行灌胃染毒,染毒剂量为10ml/kg,每天1次,连续进行14d。仔鼠于生后7～20d通过母乳染毒阿特拉津,生后21～45d自由饲养。各窝母鼠分别于染毒0、7、14d称重;仔鼠于生后9、15、28d称重,称量睾丸重量,并计算脏器系数。在仔鼠生后45d,测定仔鼠附睾中精子的存活率。结果显示,染毒阿特拉津后,各组母鼠体重均略有下降,但差异无统计学意义。各组仔鼠的体重、睾丸重量及其睾丸系数间比较,差异均无统计学意义。与对照组比较,中、高剂量阿特拉津染毒组仔鼠精子存活率较低,差异均有统计学意义(P0.05);且随着阿特拉津染毒剂量的升高,仔鼠精子存活率呈下降趋势。表明阿特拉津可以通过母鼠乳汁,降低小鼠的精子存活率。     

邻苯二甲酸二烯丙酯对子代大鼠生殖发育的影响

目的研究邻苯二甲酸二烯丙酯(diallyl phthalate,DAP)对雌性大鼠发育、生殖功能的影响。方法将96只5周龄SPF级SD大鼠按体重随机分为4组,分别为对照(玉米油)组和250、500、1 000 mg/kg DAP染毒组,每组24只,雌雄各半。采用灌胃方式进行染毒,染毒容量为2 ml/kg,每天1次。于染毒第3周后,以雌∶雄各1只进行合笼。雄性大鼠共连续染毒13周,雌性妊娠大鼠继续染毒持续到仔鼠断乳(出生后第21天,PND21)。每窝保留4只仔鼠,雌雄各半,仔鼠与母鼠同笼饲养至断乳;仔鼠断乳后至出生后第49天按性别分笼饲养,喂饲方式和染毒剂量与其亲代母鼠相同。检测两代大鼠体重及相关脏器重量,并计算脏器系数;检测两代大鼠血清甲状腺素、雌二醇、睾酮及胆固醇浓度;检测亲代大鼠的生殖情况;记录仔鼠的发育情况及精子质量。结果与对照组比较,1 000 mg/kg DAP染毒组亲代大鼠及其仔鼠肝、脾的脏器系数均增加,血清甲状腺素的浓度及雄性血清睾酮的浓度均较低,而血清胆固醇浓度均较高,差异有统计学意义(P0.05);而各剂量DAP染毒组雌性血清雌二醇的浓度均无明显改变。与对照组比较,仅1 000 mg/kg DAP染毒组大鼠交配成功时间延长,差异有统计学意义(P0.05);而各剂量DAP染毒组亲代大鼠的交配率、仔鼠数、雌雄比均无明显改变。与对照组比较,仅1 000 mg/kg DAP染毒组雌性仔鼠阴道开口时间和雄性仔鼠包皮分离时间延长,差异均有统计学意义(P0.05);而各剂量DAP染毒组雌、雄仔鼠的睁眼时间均无明显改变。与对照组比较,仅1 000 mg/kg DAP染毒组仔鼠的精子计数及精子活力较低,而精子畸形率较高,差异均有统计学意义(P0.05);且随着DAP染毒剂量的升高,仔鼠的精子计数和精子活力均呈降低趋势,而精子畸形率呈升高趋势。精子畸形主要为头部畸形(包括双头、香蕉头、无沟)。结论 DAP暴露对子代大鼠生殖发育功能有影响,其作用机制可能与DAP作为内分泌干扰物改变血清激素的水平有关。     

出生前邻苯二甲酸二(2-乙基己基)酯暴露对子代大鼠血清皮质醇激素水平的影响

目的探讨出生前邻苯二甲酸二(2-乙基己基)酯(DEHP)暴露对大鼠肾上腺功能的潜在干扰作用。方法将32只健康SD孕鼠按体重随机分为溶剂对照组(玉米油)及2、10、50 mg/kg DEHP染毒组,每组8只。自孕14~19 d连续灌胃染毒,每日1次。子代大鼠于出生后第21天断乳,雌雄分笼饲养至70日龄,断头处死,取血及双侧肾上腺,计算肾上腺脏器系数,并采用Luminex液态芯片技术测定血清皮质醇水平。结果成年雌性仔鼠肾上腺脏器系数在各染毒组间有差异,与对照组相比,2 mg/kg染毒组的肾上腺重量及脏器系数较低,差异有统计学意义(P0.05);成年雄性仔鼠肾上腺脏器系数在各染毒组间差异均无统计学意义(P0.05)。与对照组相比,10、50 mg/kg染毒组的成年雌性仔鼠血清皮质醇水平较高,差异有统计学意义(P0.01);而2 mg/kg染毒组与对照组相比无明显差异(P0.05)。与对照组相比,10 mg/kg染毒组的成年雄性仔鼠血清皮质醇水平较高,差异有统计学意义(P0.01);而2、50 mg/kg染毒组与对照组相比无明显差异(P0.05)。结论出生前DEHP暴露可能干扰子代大鼠肾上腺功能。     

妊娠期二月桂酸二丁基锡暴露对子代雄性大鼠生殖系统的影响

目的探讨妊娠期二月桂酸二丁基锡(DBTD)暴露对子代雄性大鼠性成熟后生殖系统的影响及其作用机制。方法将16只健康SPF级妊娠Wistar大鼠随机分为4组,分别为溶剂对照(玉米油)组和低(10 mg/kg)、中(20 mg/kg)、高剂量(30 mg/kg)DBTD染毒组,每组4只。采用灌胃方式进行染毒,染毒容量为5 ml/kg,自妊娠第12～20天连续染毒。仔鼠出生后第70天,每组随机抽取10只雄性大鼠,称重后处死,测定睾丸和附睾重量及其脏器系数、附睾精子数以及血清中黄体生成素(LH)、卵泡刺激素(FSH)和睾酮(T)以及睾丸组织中睾酮(T)的水平,并观察睾丸组织病理学改变。结果各剂量DBTD染毒组子代雄性大鼠体重、附睾重量及其脏器系数、血清中LH和FSH水平与溶剂对照组相比,差异均无统计学意义。与溶剂对照组比较,高剂量DBTD染毒组子代雄性大鼠睾丸重量及其脏器系数,中、高剂量DBTD染毒组子代雄性大鼠附睾精子数较高,差异均有统计学意义(P0.05或P0.01)。且随着DBTD染毒剂量的升高,子代雄性大鼠睾丸重量及其脏器系数以及附睾精子数均呈升高趋势。与溶剂对照组比较,高剂量DBTD染毒组子代雄性大鼠血清T水平和各剂量DBTD染毒组子代雄性大鼠睾丸T水平均较高,差异有统计学意义(P0.05或P0.01)。结论在本实验染毒时间和剂量范围内,孕期DBTD染毒可干扰子代雄性大鼠体内T的合成和代谢,从而促进睾丸发育和精子形成。     

DEHP亚慢性暴露对大鼠精子运动参数影响

目的观察邻苯二甲酸(2-乙基已基)酯(DEHP)染毒90 d对大鼠精子运动能力的毒性作用。方法将健康清洁级SD雄性大鼠40只随机分为对照组和3个DEHP染毒组(5、50、500 mg/kg),进行90 d经口染毒;取睾丸、附睾称重,并用扩散法收集大鼠附睾尾精子,应用计算机辅助精子分析系统(CASA)对精子的运动参数进行检测。结果 5 mg/kg DEHP组大鼠精子直线性(LIN)为(44.00±2.52)%,明显低于对照组(50.00±2.71)%(P0.05);500 mg/kg DEHP组大鼠精子鞭打频率(BCF)为(5.8±4.2)Hz,明显低于对照组(10.4±1.7)Hz(P0.05);与对照组比较,500 mg/kg DEHP组大鼠精子的平均路径速度(VAP)、直线运动速度(VSL)、曲线运动速度(VCL)、精子头侧摆幅度(ALH)、BCF明显下降,差异均有统计学意义(均P0.05);随着DEHP染毒浓度增加,大鼠精子各项运动参数逐渐降低,精子的运动能力下降。结论 DEHP对大鼠附睾精子的运动能力有直接毒性作用。     

3,4-二氯苯胺短期重复染毒对雄性大鼠精子的影响

目的研究3,4-二氯苯胺(3,4-DCA)对雄性大鼠精子的影响,以探讨3,4-DCA对雄性大鼠的生殖毒性作用。方法将40只健康成年SPF级Wistar雄性大鼠按体重随机分为39、81、170、357 mg/kg 3,4-DCA染毒组和溶剂对照组(玉米油),每组8只,经口灌胃染毒,灌胃容积为5 ml/kg,1次/d,连续染毒35 d。染毒结束后,处死大鼠,取附睾制成精子悬液,测定精子密度;台盼蓝染色测定精子的存活率,观察精子的活动能力并分级,计算精子活动率;测定精子的畸形率。结果与对照组比较,39 mg/kg 3,4-DCA染毒组体重略有增加,但差异无统计学意义(P>0.05);与对照组比较,170、357 mg/kg 3,4-DCA染毒组体重降低,差异均有统计学意义(P<0.01)。各组大鼠睾丸系数和附睾系数比较,差异无统计学意义(P>0.05)。与对照组比较,170和357 mg/kg 3,4-DCA染毒组精子密度降低,81、170、357 mg/kg 3,4-DCA染毒组精子存活率和精子活动率降低,39、81、170和357 mg/kg 3,4-DCA染毒组精子畸形率升高,差异均有统计学意义(P<0.05...     

邻苯二甲酸二甲酯对雄性小鼠生殖系统的影响

目的探讨邻苯二甲酸二甲酯(DMP)的生殖毒性作用。方法以成年雄性ICR小鼠为研究对象,设1 000 mg/kg、500 mg/kg、250 mg/kg剂量和对照组连续染毒2个月。测定脏器系数、精子运动及精子数、睾丸细胞酶活力及部分血清生化指标。结果 DMP能引起雄鼠500 mg/kg和1 000 mg/kg染毒组睾丸重量减少(P0.01),各染毒组附睾重量均减少(P0.01),500 mg/kg和1 000 mg/kg染毒组肝脏肿大(P0.01); 1 000 mg/kg染毒组Ⅰ级、Ⅳ级运动精子、精子数与对照组比较差异有统计学意义(P0.01);各染毒组AKP活力比对照组均显著降低(P0.01);各染毒组血清Cr、1 000 mg/kg染毒组UREA都显著升高,与对照组比较差异有统计学意义(P0.01)。结论 DMP对雄性小鼠具有一定生殖毒性作用,睾丸细胞酶活力的改变,可能与DMP导致睾丸的支持细胞和生精上皮细胞损伤作用有关。     

大鼠新生期暴露2,2',4,4',5,5'-六氯联苯对精子发生的影响

目的 探讨新生期SD大鼠暴露持续性有机污染物2,2',4,4',5,5'-六氯联苯(PCB153)对大鼠精子发生的远期效应.方法 大鼠出生当天(postnatal day O,PNDO),将所有雄性大鼠混合后,重新分为12只,窝.在出生1 d(PND1),按窝别随机分成对照组和处理组,每组24只雄性大鼠.自PND1开始连续7 d经口给予PCB153 0.025、0.250、2.500 mg/kg和等量溶剂对照玉米油.在PND8,每组随机选择16只大鼠称重和测肛殖距离后,经乙醚麻醉并处死,分离和称重睾丸后作组织学检查.剩余大鼠在PND21断奶并饲养至PND90,称重和测肛殖距离后经质量分数为10%的水合氯醛麻醉后解剖,分离并称重睾丸和附睾,其中睾丸用作组织学检查和精子头计数,附睾尾作精子计数.结果 从PND3至PND8,2.500 mg/kg剂量组体重与对照组相比明显下降,差异有统计学意义(P<0.05);在光学显微镜和电子显微镜下观察显示,PND8睾丸组织曲精小管结构疏松,精原细胞体积增大、变性并与管内结构相脱离.随着染毒剂量的增加,PND90睾丸每日精子生成量和附睾尾精子计数与染毒剂量呈剂量-反应关系(r值分别为-0.97和-0.99,P<0.05).0.250和2.500mg/kg剂量组的每日精子生成量分别为30x106/g睾丸和18×106/g睾丸,与对照组(36×106/g睾丸)相比,差异有统计学意义(P<0.05);0.250和2.500 mg/kg剂量组附睾尾精子计数分别为42×107/g附睾尾和18x107/g附睾尾,明显低于对照组(51×107/g附睾尾),差异均有统计学意义(P<0.05).结论 SD大鼠新生期暴露PCB153,可引起成年期睾丸生精功能障碍,导致每日精子生成量和附睾尾精子计数下降.新生期化学物暴露可能引起雄性大鼠生殖功能的远期损害.     

孕期二月桂酸二丁基锡暴露对子代大鼠睾丸酶活力和生精功能的影响

目的 探讨孕期接触二月桂酸二丁基锡(DBTD)对Wistar大鼠子代雄性鼠性成熟后睾丸酶活力和生精功能的影响.方法 以0、10、20和30 mg/kg剂量的DBTD溶液对妊娠第12天的Wistar孕鼠连续灌胃染毒至第20天,仔鼠出生后第70天,每组随机抽取10只雄性大鼠,称重并处死,测定睾丸脏器系数、附睾精子数,并采用分光光度法测定睾丸酶活力.结果 各剂量组孕鼠染毒期间体重增加量、产仔数、仔鼠雌雄比例及子代雄性大鼠体重与对照组比较,差异均无统计学意义(P＞0.05);30 mg/kg组睾丸重量和睾丸脏器系数高于对照组,差异有统计学意义(P＜0.01,P＜0.05);20和30 mg/kg组精子数高于对照组,差异有统计学意义(P＜0.05,P＜0.01).各剂量组琥珀酸脱氢酶(SDH)活力和一氧化氮合酶(NOS)活力与对照组比较,差异无统计学意义(P＞0.05);10和20 mg/kg组酸性磷酸酶(ACP)活力、10 mg/kg组乳酸脱氢酶(LDH)活力、30 mg/kg组一氧化氮(N0)含量均高于对照组,差异有统计学意义(P＜0.05).结论 在本实验染毒时间和剂量范围内,DBTD对子代雄性大鼠睾丸发育和精子形成有促进作用,而对睾丸酶活力无直接影响.     

孕期及哺乳期经口邻苯二甲酸二(2-乙基己基)酯染毒对大鼠的生殖毒性

目的 观察邻苯二甲酸二(2-乙基己基)酯(DEHP)对大鼠的生殖发育毒性作用.方法 采用围生期毒性试验的研究方法,将清洁级SD大鼠随机分为对照组(玉米油)和4个DEHP染毒组(125、250、500、1 000mg/kg),采用宫内及哺乳期经口灌胃的方式染毒.记录比较孕鼠孕0、20天(GD0、GD20)、仔鼠出生后21天(PND21)母鼠体重及体重增长量,产后第1天(PND1)记录产仔总数及仔鼠平均出生体重;产后第4天(PND4)辨别雌雄仔鼠,分别测量雌雄仔鼠平均肛殖距,于仔鼠断乳(PND21)后,计数着床数,取母鼠各脏器称重并计算脏器系数.结果 母鼠染毒期间,体重及其体重增长量不同程度降低(P＜0.05),各脏器系数均不同程度增大(P＜0.01),各染毒组受孕率差异有统计学意义(χ~2=16.816,P＜0.01);与对照组比较,1 000mg/kg组仔鼠平均活胎数、平均出生体重、子宫着床点数降低(P＜0.05),肛殖距不同程度缩短(P＜0.01).结论 DEHP可降低雌鼠受孕率及母鼠产仔总数,可通过胎盘屏障对仔鼠的生长发育产生毒性作用,导致低出生体重,对仔鼠的生殖发育有毒性作用.

Abstract：

Objective To observe the procreating and developing toxicity effect of phthalate(2-ethylhexyl)ester on rats.Methods The perinatal toxicity test methods was applied,the negative control group(corn oil)and four DEHP exposure groups(125,250,500,1000 mg/kg)were set,the SD pregnant rats were treated with DEHP by gavage.GD0,GD20,PND21 pregnant rats body weight and weight increase were recorded and compared.At PND1,the total number of birth and average birth weight of young rats were recorded;At PND4 male and female rats were distinguished,male and female rats were measured for average anogenital distance.After weaning(PND21),pregnant rats were killed,the numbers of implantation were counted,organs were weighted and organ coefficients were calculated.Results During exposure to different doses of DEHP,pregnant rats body weight and body weight increase reduced in degrees(P＜0.05),the organ coefficients were increased in degrees(P＜0.01),the pregnancy rate of exposure groups showed statistically differences(χ~2=16.816,P＜0.01);Compared with control group,the average number of live births and the average birth weight,the number of uterine implantation of the 1 000 mg/kg group reduced(P＜0.05),anogenital distance reduced in degrees(P＜0.01).Conclusion DEHP can reduce female conception rates and the litter size,may have the toxic effect through the placental barrier on the growth of rats,leading to low birth weight,and have the toxic effect on the reproductive development of rats.     

Effects of in utero and lactational exposure to di(2-ethylhexyl)phthalate on somatic and physical development in rat offspring

Di(2-ethylhexyl)phthalate (DEHP) has been reported to act as an antiandrogen and to affect the reproductive organs and accessory genital glands. Thus, to assess the reproductive toxicity of DEHP it is important to examine both its adverse effects on the development of offspring following maternal exposure and its effects on sexual function and fertility. In the present study, we examined whether in utero and lactational exposure to DEHP affects postnatal somatic growth of offspring in the rat. Pregnant females were orally administered various doses of DEHP (0, 25, 100 or 400 mg/kg body weight/day) from gestational day (GD) 6 through postnatal day (PND) 20. There were no significant changes in body weight, body length, tail length, or the weight of individual organs between the control and DEHP-treated groups. Somatic hormonal parameters were the same for all DEHP doses. These findings suggest that in utero and lactational exposure to various concentrations of DEHP has very little effect on postnatal development or endocrine and physical status of male and female rat offspring under the experimental conditions of the present study.     

Abnormalities of sexual development in male rats with in utero and lactational exposure to the antiandrogenic plasticizer Di(2-ethylhexyl) phthalate

Several members of the phthalate ester family have antiandrogenic properties, yet little is known about how exposure to these ubiquitous environmental contaminants early in development may affect sexual development. We conducted experiments to determine effects of in utero and lactational exposure to the most prevalent phthalate ester, di(2-ethylhexyl) phthalate (DEHP), on male reproductive system development and sexual behavior. Sprague-Dawley rats were dosed with corn oil or DEHP (0, 375, 750, or 1,500 mg/kg/day, per os) from gestation day 3 through postnatal day (PND) 21. Dose-related effects on male offspring included reduced anogenital distance, areola and nipple retention, undescended testes, and permanently incomplete preputial separation. Testis, epididymis, glans penis, ventral prostate, dorsolateral prostate, anterior prostate, and seminal vesicle weights were reduced at PND 21, 63, and/or 105-112. Additional dose-related effects included a high incidence of anterior prostate agenesis, a lower incidence of partial or complete ventral prostate agenesis, occasional dorsolateral prostate and seminal vesicle agenesis, reduced sperm counts, and testicular, epididymal, and penile malformations. Many DEHP-exposed males were sexually inactive in the presence of receptive control females, but sexual inactivity did not correlate with abnormal male reproductive organs. These results suggest that in utero and lactational DEHP exposure also inhibited sexually dimorphic central nervous system development. No major abnormalities were found in any of eight control litters, but DEHP caused severe male reproductive system toxicity in five of eight litters at 375 mg/kg/day, seven of eight litters at 750 mg/kg/day, and five of five litters at 1,500 mg/kg/day. These results demonstrate that the male reproductive system is far more sensitive to DEHP early in development than when animals are exposed as juveniles or adults. The effects of DEHP on male reproductive organs and sexual behaviors and the lack of significant effects on time to vaginal opening and first estrus in their littermates demonstrate that DEHP (and/or its metabolites) affects development of the male reproductive system primarily by acting as an antiandrogen. The pattern of effects of in utero and lactational DEHP exposure differed from patterns caused by other phthalate esters, and the preponderance of anterior prostate agenesis appears to be unique among all chemicals. These results suggest that DEHP acts partly by mechanisms distinct from those of other antiandrogens.     

邻苯二甲酸二丁酯宫内和哺乳期染毒对F_1代雄性大鼠的生殖发育毒性

目的　观察邻苯二甲酸二丁酯 (DBP)对F1代仔鼠的发育状况及性成熟期雄性仔鼠生殖系统损害情况 ,并期望得到现有文献中缺如的DBP对F1代仔鼠生殖发育毒性的最大无作用剂量 (NOAEL)。方法　选择在宫内暴露期和哺乳期 (受孕第 2天至仔鼠 2 1天断奶 ) ,通过灌胃方式给母鼠染毒 (DBP终浓度分别为 0、5 0、2 5 0和 5 0 0mg (kg·d) ,观察对仔鼠的影响。结果　DBP对母鼠无明显影响 ,中高剂量组 [2 5 0、5 0 0mg (kg·d) ]对F1代雄性仔鼠的出生体重、每窝活产数、体重增长及雄性仔鼠肛殖距有明显影响 ,对性成熟期雄性仔鼠生殖系统损害尤为严重 ,可观察到小睾丸、附睾发育不全甚至缺失、睾丸未降等现象 ,附睾尾精子参数和睾丸精子头计数及附睾、肝、肾、前列腺的脏器系数明显降低 ,而与激素合成相关的垂体系数却略有上升。低剂量组未观察到有害影响。结论　雄性生殖系统是DBP作用的主要靶器官 ,幼年敏感期所受的损害部分不可逆 ,并得到DBP经口染毒对F1代仔鼠生殖发育毒性的NOAEL为 5 0mg (kg·d)。据此 ,进一步提出DBP经口摄入的参考剂量 (RfD)为 5 0 0 μg (kg·d)。     

性别分化关键期三丁基氯化锡暴露对大鼠生精功能和睾丸酶活力的影响

目的 探讨性别分化关键期三丁基氯化锡(TBTC)暴露对大鼠性成熟后睾丸酶活力和生精功能的影响.方法 将16只健康成年SPF级妊娠Wistar大鼠随机分为高(5.0 mg/kg)、中(2.5mg/kg)、低剂量(1.0 mg/kg)TBTC染毒组和溶剂对照组(玉米油),每组4只.从妊娠第12天起,采用经口灌胃方式进行染毒,每天1次,直至妊娠第20天,灌胃剂量为5.0ml/kg.出生后第70天,每组随机抽取10只雄性仔鼠,称重后处死,分离双侧睾丸及附睾组织,测定附睾精子数及睾丸酶[乳酸脱氢酶(LDH)、琥珀酸脱氢酶(SDH)、酸性磷酸酶(ACP)、一氧化氮合酶(NOS)]活力.结果 与溶剂对照组比较,各TBTC染毒组孕鼠妊娠第12天及第20天的体重和体重增长量差异无统计学意义(P>0.05).与溶剂对照组比较,高、中剂量TBTC染毒组雄性仔鼠断乳后体重增长较慢,差异均有统计学意义(P<0.01). TBTC染毒组附睾尾精子数随TBTC染毒剂量的升高呈上升趋势,差异有统计学意义(P<0.01).与溶剂对照组相比,高、中、低剂量TBTC染毒组雄性仔鼠LDH活力较高,高、中剂量TBTC染毒组雄性仔鼠SDH活力较高,差异均有统计学意义(P<0.01).各TBTC染毒组雄性仔鼠ACP和NOS活力间比较,差异均无统计学意义(P＞0.05).未发现睾丸组织结构发生改变.结论 性别分化关键期TBTC染毒对雄性仔鼠具有内分泌干扰作用,减缓了雄性仔鼠的体重增长,促进了其精子发生和LDH、SDH的活力.

Abstract：

Objective To explore the effects of exposure to tributyltin chloride (TBTC)during the critical period for sex differentiation on activities of enzymes in testis and spermatogenesis function in Wistar rats.Methods Sixteen healthy adult pregnant Wistar rats were randomly divided into four groups(5,2.5 and 1 mg/kg TBTC,vehicle control)with 4 animals per dose group.They were given doses of TBTC by gavage from days 12-20 of gestation once a day.The volume of the vehicle used was 5 ml/kg body weight.On the postnatal day (PND)70,ten male offsping rats were randomly selected in each group and sacrificed by decapitation after weighed.The sperms in epididymis were counted and the activities of enzymes of testis[including lactate dehydrogenase (LDH),succinate dehydrogenase (SDH),acid phosphatase (ACP),nitric oxide synthase (NOS)]were detected.Several testises were chosen for the histopathological examination.Results The body weight gains of pregnant rats from days 12-20 showed no significant difference among the solvent control group and the each TBTC exposure group (P>0.05).Compared with the control group,body weights gains from PND21-70 were decreased significantly in the 5 and 2.5 mg/kg group (P＜0.01).Cauda epididymal sperm counts increased with the increase of TBTC doses (P<0.01).The activities of LDH in all treated groups and the activities of SDH in the 5 and 2.5 mg/kg TBTC group exhibited significant increase compared with the control group (P＜0.01).There were no significant difference in the activities of ACP and NOS between the exposure groups and the control group(P>0.05).No abnormal structure of testis was observed in all exposure groups.Conclusion Exposure to TBTC during critical period for sex differentiation may decrease body gain and increase spermatogenesis and the activities of LDH and SDH.     

Maternal exposure to 2,3,7,8-tetrachlorodibenzo-<Emphasis Type="Italic">p</Emphasis>-dioxin and the body burden in offspring of long-evans rats

Objectives   In utero and lactational exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) results in a wide variety of developmental effects in pups at doses much lower than those causing overt toxicity in adult animals. We investigated the relationship between tissue concentrations of TCDD in dams and fetuses and developmental effects on pups. Materials and Methods  Pregnant Long-Evans rats were given TCDD at a single oral dose of 12.5, 50, 200, or 800 ng of TCDD or [³H]-TCDD/kg bw on gestation day (GD) 15. Dams were sacrificed on GD16 and GD21, and the tissue concentrations of TCDD were measured in dams and fetuses. Pups were sacrificed on postnatal day (PND) 49 and PND63 for males and PND70 for females, and the reproductive effects and tissue concentrations of TCDD were determined. Results  The sex ratio (male/female) on GD21 was significantly reduced at 50 ng TCDD/kg and at 12.5 and 50 ng TCDD/kg at birth, but not at other doses. Delayed puberty was observed in males at 200 ng TCDD/kg and in males and females at 800 ng TCDD/kg. Anogenital distance, testis weight, epididymal sperm count, sperm motility, and ejaculated sperm count were not affected. Estrous cyclicity was not different from that of the control in any treatment group. A dose-dependent decrease in weight of seminal vesicle and prostate on PND49 was observed. Prostate weight was significantly decreased at 800 ng TCDD/kg. At this dose, maternal body burden and TCDD concentration in fetuses were 290 pg TCDD/g and 52 pg TCDD/g on GD16, respectively. Reduced prostate weight is a sensitive and commonly observed endpoint so that the body burdens of dams and fetuses at the LOAEL of this endpoint could be served as the basis for establishing TDI for dioxins.     

胚胎期暴露DEHP对子代大鼠神经行为的影响

目的通过邻苯二甲酸二(2-乙基己基)酯(DEHP)胚胎期暴露,评价其对子代大鼠神经行为的影响,初步探讨DEHP所致子鼠神经毒性的机制。方法雌性Wistar大鼠从妊娠日起用10、100、500 mg/(kg.d)DEHP连续灌胃染毒19 d,观察子代大鼠的神经行为学指标。于子鼠出生第7天和第21天测定海马神经细胞凋亡率,不同剂量的DEHP染毒对海马组织bcl-2、bax基因的表达的影响。结果于子鼠出生6周后,进行水迷宫测试。结果显示,随着DEHP剂量增加,中、高剂量组错误次数增加和潜伏期延长十分明显(F=8.058,P<0.05;F=11.221,P<0.05)。电穿梭测试显示,中、高剂量组电击次数增加和主动逃避时间延长较为明显(F=6.984,P<0.05;F=9.841,P<0.05)。出生后7 d子代大鼠海马神经元的细胞凋亡率高于出生21 d,高剂量组尤为显著。RT-PCR检测表明,与对照组相比,bcl-2和bax基因表达增高(F=253.78,P<0.05;F=66.67,P<0.05),且随着DEHP暴露剂量的升高,表达亦增加。结论 DEHP对子代大鼠神经系统具有明显的毒性作用,存在着剂量-反应关系,其可能通过干扰bcl-2和bax基因的表达而影响子代大鼠神经系统发育。