不同孕期铅暴露对大鼠妊娠结局及胎盘MMP-9、TIMP-1表达的影响

[目的]通过观察Wistar大鼠孕期不同时段铅暴露对妊娠结局及胎盘基质金属蛋白酶-9（MMP-9）、基质金属蛋白酶组织抑制因子-1（TIMP-1）的表达影响,评价孕早期、孕后期及孕全程铅暴露的毒性特点及毒性机制。[方法]108只Wistar大鼠随机分为4组,每组27只（雌雄为21）,用0.025%醋酸铅对各实验组的孕鼠通过自由饮服的方式染：：毒。实验A组：孕早期（1～10d）饮服0.025%醋酸铅,孕后期（11～20d）饮服蒸馏水;实验B组：孕早期（1～10d）饮服蒸馏水,孕后期（11～20d）饮服0.025%醋酸铅;实验C组：孕期全程（1～20d）饮服0.025%醋酸铅。根据大鼠孕期3周推算,足月进行麻醉剖腹取胎,观察胎盘及仔鼠体重、身长、尾长、仔鼠数等;同时采集腹腔静脉血,用原子吸收光谱仪测定各组大鼠孕末期血铅水平。免疫组化法测定胎盘滋养细胞MMP-9、TIMP-1的表达。[结果]实验组孕末期血铅水平与对照组比较差异均有统计学意义（P〈0.01）。各组胎盘重量及仔鼠体重、身长、尾长差异也有统计学意义（P〈0.01）,其中实验C组最低,分别为（0.31±0.13）g、（2.08±0.88）g、（2.37±0.32）cm、（0.98±0.09）cm。血铅水平与胎盘重量呈负相关（r=-0.652,P〈0.01）。孕全程染铅组胎盘MMP-9表达下降,TIMP-1表达增强。[结论]孕期不同时段铅暴露导致不同的妊娠结局。孕全程染铅的孕末期血铅水平最高,对胎盘及仔鼠影响最大。胎盘MMP-9表达下降、TIMP-1表达增强可能是铅致胎盘损伤的病理机制之一。     

不同孕期铅暴露对大鼠妊娠结局及胎盘TIMP-1表达的影响

目的:观察孕期不同时段铅暴露对妊娠结局及胎盘TIMP-1表达的影响,探讨孕早期、孕后期及孕全程铅暴露的毒性特点及毒性机制。方法:采用原子吸收光谱仪测定孕期不同阶段低水平铅暴露后的大鼠孕末期血铅水平。0.025%醋酸铅对实验组孕鼠染毒,根据大鼠孕期3周推算足月剖宫产,观察异常分娩情况,记录胎盘质量、仔鼠数、仔鼠质量。免疫组化法测定胎盘滋养细胞TIMP-1的表达。结果:孕早期染铅对孕末期血铅水平及胎盘质量的影响较大,孕晚期染铅对仔鼠重量的影响较明显,孕全程染铅对孕末期血铅水平、胎盘质量及仔鼠质量均有明显影响。孕全程染铅组其胎盘TIMP-1表达最强。结论:铅具有生殖毒性及胚盘毒性,孕期不同时段铅暴露导致不同的妊娠结局。胎盘TIMP-1表达增强可能是铅致胎盘损伤的病理机制之一。     

孕期不同阶段铅暴露对大鼠妊娠结局的影响

[目的]通过孕期不同时段铅暴露,探讨孕早期、孕后期及孕全程铅暴露对大鼠妊娠结局的影响.[方法]0.025%醋酸铅对实验组孕鼠染毒,用原子吸收光谱仪测定孕期不同时段低水平铅暴露后大鼠孕末期血铅水平,统计异常分娩情况,记录仔鼠数和仔鼠体重.[结果]铅暴露组大鼠异常妊娠率增高,但各组间差异无显著性（P＞0.05）.实验组孕鼠孕末期血铅水平均高于0.483umol/I,组间差异有非常显著性（P＜0.01）.实验组仔鼠体重减轻,各组间差异有非常显著性（P＜0.01）.[结论]胚胎期经胎盘“染铅”,是导致子代铅蓄积的重要原因.孕期不同时段铅暴露对仔鼠生长发育产生危害.     

Smad4在孕期不同阶段铅暴露大鼠胎盘中的表达

目的观察孕期不同阶段铅暴露对大鼠胎盘中信号蛋白Smad4表达的影响。方法将72只健康清洁级Wistar妊娠大鼠随机分为4组,分别为孕早期铅暴露组[孕早期(妊娠1～10 d)饮用0.25g/L乙酸铅溶液染毒,孕晚期(妊娠11～20 d)饮用蒸馏水],孕晚期铅暴露组(孕早期饮用蒸馏水,孕晚期饮用0.25g/L乙酸铅溶液染毒),孕全期铅暴露组[孕期全程(妊娠1～20 d)饮用0.25 g/L乙酸铅溶液染毒],对照(蒸馏水)组,每组18只。测定孕末期腹腔静脉血铅水平;足月剖宫取胎盘并称重,统计不同妊娠结局。并测定大鼠胎盘中Smad4的表达。结果剔除自然分娩与异常妊娠结局大鼠后,最终入组大鼠分别为:孕早期铅暴露组16只,孕晚期铅暴露组15只,孕全期铅暴露组15只,对照组17只。大鼠孕末期血铅水平由低至高依次为对照组<孕晚期铅暴露组<孕早期铅暴露组<孕全期铅暴露组,胎盘重量由高至低依次为对照组>孕早期铅暴露组>孕晚期铅暴露组>孕全期铅暴露组,任意两组比较,差异均有统计学意义(P<0.05)。大鼠胎盘重量与孕末期血铅水平呈显著负相关(r=-0.652,P<0.01)。与对照组比较,各实验组大鼠胎盘中Smad4的表达均升高,差异均有统计学意义(P<0.05)。与孕早期铅暴露组比较,孕晚期及孕全期铅暴露组大鼠胎盘中Smad4的表达均下降,差异均有统计学意义(P<0.05)。结论铅暴露使得胎盘中Smad4的表达升高,早期铅暴露时Smad4的表达水平明显高于晚期铅暴露组及全程铅暴露组,血铅水平增高导致Smad4表达的异常可能是致胎盘损伤的毒性机制之一。     

染铅大鼠胎盘MMP-9、TIMP-1表达与血铅水平的相关性

目的 观察孕期不同阶段铅暴露大鼠胎盘组织中基质金属蛋白酶-9和组织抑制因子-1的表达特征及其与孕末期血铅水平的相关性.方法 108只大鼠随机分为4组,于孕期不同阶段饮服0.025%醋酸铅.对照组孕期全程饮服蒸馏水;实验A组孕早期饮服醋酸铅,孕后期饮服蒸馏水;实验B组孕早期饮服蒸馏水,孕后期饮服醋酸铅;实验C组孕期全程饮服醋酸铅.孕末期腹腔静脉取血,用原子吸收光谱法测定血铅水平,用免疫组化法测定胎盘滋养层细胞中基质金属蛋白酶-9和组织抑制因子-1的表达.结果 ①对照组孕鼠孕末期平均血铅水平为0.04±0.01μmol/L,实验组孕鼠孕末期平均血铅水平均高于0.48μmol/L,以实验C组血铅水平最高;②基质金属蛋白酶-9和组织抑制因子-1在胎盘组织中的表达部位主要位于滋养层细胞胞质;③胎盘滋养层细胞基质金属蛋白酶-9的表达4组间总体比较差异有统计学意义(χ2=28.381,P<0.01),孕末期血铅水平轻度升高时基质金属蛋白酶-9表达阳性率增加,当血铅水平进一步升高后,基质金属蛋白酶-9表达阳性率反而下降,以血铅水平最高的实验C组阳性表达率最低,与对照组比较差异有统计学意义(χ 2=8.402,P<0.05);④胎盘滋养层细胞组织抑制因子-1的表达4组间总体比较差异有统计学意义(χ2=18.177,P<0.05),实验A、C组与对照组比较差异有统计学意义(χ2分别为10.688、8.720,均P<0.05),其表达强度随着孕末期血铅水平的增高而增强,呈剂量-效应关系.结论 孕鼠孕末期血铅水平与胎盘滋养层细胞基质金属蛋白酶-9和组织抑制因子-1的表达强度密切相关,以血铅水平最高的实验C组改变最为明显.血铅水平增高引起的基质金属蛋白酶-9和组织抑制因子-1表达失衡可能是铅致胎盘组织损伤的毒性机制之一.     

孕期铅暴露大鼠胎盘血栓调节蛋白表达

目的观察孕期不同阶段铅暴露对大鼠胎盘血栓调节蛋白(thrombomodulin,TM)表达的影响,探讨铅胎盘毒性机制。方法 108只大鼠随机分为对照组与孕早、晚期和全程醋酸铅染毒组;对照组孕期饮服蒸馏水,醋酸铅染毒组于不同孕期给予0.025%醋酸铅染毒;原子吸收光谱法测定血铅;荧光定量PCR法测定TM mRNA表达;免疫组织化学方法测定TM蛋白表达。结果对照组胎盘组织中TM蛋白表达(吸光度A值)为(0.110±0.023),与对照组比较,孕早、晚期染毒组TM蛋白表达水平降低,孕全程染毒组升高,差异有统计学意义(P0.01);孕早、晚期和全程醋酸铅染毒组TM基因mRNA表达量分别为(0.819±0.117),(0.995±0.065)和(1.213±0.128),与对照组比较差异有统计学意义(P0.001)。结论孕期不同阶段铅暴露可影响TM蛋白和基因mRNA表达,TM表达异常可能是孕期铅暴露致胎盘损伤的重要机制之一。     

子宫内铅暴露对仔鼠牙齿萌出和釉质发育的影响

目的观察母鼠妊娠期间不同剂量铅暴露对仔鼠牙齿萌出情况和釉质发育的影响。方法27只怀孕SD大鼠随机分为铅暴露高剂量组、低剂量组和对照组,每组9只。铅暴露组饮用去离子水中加入醋酸铅进行染毒[以铅(Pb2+)含量计算高剂量组200mg/L、低剂量组50mg/L],对照组饮用去离子水。染毒自大鼠孕第1天持续至自然分娩。仔鼠出生后第26天在下切牙龈乳头水平进行第1次标记,并于出生后第36天在同一牙龈乳头水平行二次标记。第2次标记当日取全血测定血铅并处死仔鼠。测定切牙铅含量,应用立体显微镜观察牙齿形态并测量切牙两次标记间距离,应用电子探针测定切牙釉质钙、磷含量并计算比值。结果高、低剂量铅暴露仔鼠组血铅较对照仔鼠组增高,差异有统计学意义(P<0.01);高、低剂量铅暴露仔鼠组齿铅[(77.3±6.3)、(27.8±4.5)μg/g]与对照仔鼠组[(6.6±0.8)μg/g]相比,差异有统计学意义(P<0.01)。铅暴露仔鼠组切牙较小,牙尖磨耗明显并多见舌侧髓腔暴露,高铅剂量组更为明显。高、低剂量铅暴露仔鼠组切牙萌出速率[(0.25±0.08)、(0.30±0.09)mm/d]与对照仔鼠组[(0.39±0.09)mm/d]比较,铅暴露组萌出较为缓慢,三组间差异有统计学意义(P<0.01)。仔鼠釉质钙/磷比分析显示,随铅染毒剂量的增加,钙/磷比(1.68±0.54、1.37±0.47)降低,     

S100B蛋白在不同孕期铅暴露大鼠胎盘中的表达

目的观察S100B蛋白在孕期不同阶段铅暴露下大鼠胎盘中的表达特征。方法 108只大鼠随机分为4组,于孕期不同时期饮服0.025%醋酸铅溶液;原子吸收光谱法测定孕末期血铅水平;免疫组化法测定胎盘组织中S100B蛋白的表达。计量资料组间比较采用单因素方差分析,计数资料组间比较采用卡方检验。结果实验组血铅水平均高于0.483μmol/L,与对照组比较差异有统计学意义(F=12.10,P=0.000);S100B蛋白主要表达于大鼠胎盘细胞滋养层细胞、蜕膜细胞及血管壁细胞胞质中,实验组阳性表达率高于对照组(52.94%),且孕期全程铅暴露组(93.33%)高于孕早期(87.50%)和孕晚期铅暴露组(80.00%),差异有统计学意义(χ2=18.62,P=0.029)。结论 S100B蛋白的表达与孕期铅暴露大鼠血铅水平相关,推测其在铅致胎盘的损伤中起重要作用。     

不同孕期铅暴露对大鼠妊娠结局及胎盘MMP-9、TIMP-1表达的影响

通过观察Wistar大鼠孕期不同时段铅暴露对妊娠结局及胎盘基质金属蛋白酶-9（MMP-9）、基质金属蛋白酶组织抑制因子-1（TIMP-1）的表达影响,评价孕早期、孕后期及孕全程铅暴露的毒性特点及毒性机制。研究人员将108只Wistar大鼠随机分为4组,每组27只（雌：雄为2：1）,用0.025%醋酸铅对各实验组的孕鼠通过自由饮服的方式染毒。     

注射用环磷酰胺对大鼠致畸敏感期毒性研究

目的 观察环磷酰胺1次染毒或连续染毒对大鼠致畸敏感期的毒性反应.方法 选用SD大鼠,设对照组(生理氯化钠)、7.0、15.0 mg/kg染毒组,每组6只孕鼠.15.0 mg/kg组于孕第12天1次皮下注射染毒;7 mg/kg组于孕第11～13天连续皮下注射染毒3次.观察孕鼠体质量及一般健康状况,于妊娠第20天解剖并记录子宫连仔鼠质量、胎盘质量、仔鼠体质量、黄体数、死仔和活仔鼠数、仔鼠身长和尾长;检查仔鼠外观、骨骼和内脏.结果 ①2个染毒组的孕鼠染毒后均很快出现毒性反应,精神状态明显变差、活动减少、体质量减轻;②7.0和15.0 mg/kg染毒组死仔率分别为60.29%和18.37%,明显高于对照组的1.69%(P＜0.05);子宫连仔质量、胎盘质量、鼠仔体质量、身长、尾长均明显低于对照组(P＜0.05);③染毒组存活仔鼠普遍发生脑膜膨出,骨骼骨化不全,15.0 mg/kg组仔鼠大多数出现并趾、少趾、足外翻、短肋、缺肋等异常.结论 大鼠致畸敏感期1次(15.0 mg/kg)或连续3次(7.0 mg/kg)皮下注射环磷酰胺,均可导致明显的胚胎毒性反应,毒性反应的严重程度与染毒时间和剂量密切相关.     

Alcohol inhibition of suckling-induced prolactin release in lactating rats: threshold evaluation

Prolactin release in response to suckling was examined in primiparous lactating rats two hours after alcohol administration. Litters were adjusted to eight pups on lactation day 2 and dams were implanted with an atrial catheter on day 6. On day 10, pups were separated from the mother at 0800 h. An extension was attached to the catheter at 1100 h. Following removal of a baseline blood sample an hour later, rats were infused with alcohol doses of 0, 0.5, 1.0, 2.0 or 2.5 g/kg body weight. Two hours later, pups were returned to dams. Subsequent blood samples were obtained 10, 30, 60, 120 and 180 min after the onset of suckling. Following 10 min of suckling, plasma prolactin for groups of rats infused with alcohol at 2.0 and 2.5 g/kg body weight were lower than control, 0.5 and 1.0 g/kg groups. The blood alcohol level (BAL) for the 2.0 g/kg group was 94 +/- 8 mg% and for the 2.5 g/kg group was 162 +/- 4 mg%. After 30 min, the BAL for the 2.5 g/kg group was 134 +/- 5 mg% and plasma prolactin was suppressed in this group compared to control, 0.5 and 1.0 g/kg groups. The BAL for the 2.0 g/kg group after 30 min of suckling was 74 +/- 9 mg% but prolactin was not significantly lower than controls. We conclude that in rats, alcohol inhibition of suckling-induced prolactin release is directly correlated to the BAL. The threshold BAL which effectively inhibits this prolactin release is lower than the human legal intoxication level.     

腺苷蛋氨酸对发育期铅暴露大鼠的保护作用及其长时程增强机制研究

目的 探讨S-腺苷L-蛋氨酸(S-adenosyl-L-methionine,SAM)对发育期慢性铅暴露大鼠血铅浓度、肝脏、脑、海马组织氧化损伤的影响,及其对铅暴露引起的长时程增强(long-term potentiation,LTP)和双脉冲易化(paired-pulse facilitation,PPF)的损伤的修复作用.方法 采用抽签法将受孕Wistar大鼠按每组3只随机分为3组:对照组,全程饮用自来水,仔鼠断乳后每天腹腔注射生理盐水;染铅组,孕期与哺乳期染铅,仔鼠断乳后每天腹腔注射生理盐水;铅+SAM注射组,孕期与哺乳期染铅,仔鼠断乳后每天腹腔注射20 mg/kg的SAM,22 d后测定各组仔鼠血铅浓度和肝脏、脑、海马组织氧化指标,并在位记录各组大鼠海马齿状回PPF和LTP.结果 对照组、染铅组和铅+SAM组血铅浓度分别为(27.5±3.8)、(159.3±10.9)、(33.1±9.5)μg/L,铅+SAM组与染铅组比较差异有统计学意义(F=213.5,P＜0.01);SAM能提高染铅组肝脏、脑组织的谷胱苷肽(GSH)水平、降低丙二醛(MDA)水平,与染铅组比较差异均有统计学意义(P＜0.05);与对照组兴奋性突触后电位(field excitatory postsynaptic potential,EPSP)LTP幅度[(131±4.5)%]相比,染铅组LTP[(112±2.1)%]明显下降,而铅+SAM组能修复LTP至(120±2.6)%,差异有统计学意义(F=26.1,P＜0.05).结论 SAM对临床上慢性铅中毒儿童尤其是学习记忆损伤的修复可能具有一定作用.     

Prenatal ethanol exposure during the last third of gestation in rat reduces hippocampal NMDA agonist binding site density in 45-day-old offspring.

The effect of ethanol exposure during different periods of prenatal or postnatal development on hippocampal N-methyl-D-aspartate (NMDA) receptor binding was studied in rat. Fetal rat pups were exposed to ethanol for different periods of time during gestation via maternal consumption of a 3.35% ethanol liquid diet. In a separate experiment, neonatal pups were fed 2.51 g ethanol/kg body weight/day from Postnatal Day (PD) 4 to PD 10 via intragastric feeding tube. These two ethanol administration paradigms produced average peak maternal and pup blood ethanol concentrations of 39 mg/dl and 57 mg/dl, respectively. At 45 days of age, offspring from each treatment group were sacrificed for measurements of hippocampal NMDA-sensitive [3H]-glutamate binding site density using in vitro radiohistochemical techniques. As observed previously, prenatal ethanol exposure throughout gestation resulted in NMDA-sensitive [3H]-glutamate binding site reductions in the apical dendritic field regions of dentate gyrus, hippocampal CA1 and subiculum of dorsal hippocampal formation compared to the ad lib or pair-fed control groups. NMDA-sensitive [3H]-glutamate binding was not different than control in rats exposed to ethanol during the first half of gestation only. Prenatal ethanol exposure during the last half or the last third of gestation resulted in NMDA-sensitive [3H]-glutamate binding site reductions comparable to the binding site reductions observed in rats exposed to ethanol throughout gestation. Hippocampal NMDA-sensitive [3H]-glutamate binding site density in postnatal ethanol-exposed rats was not different than the suckling or gastrostomy control groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

大豆异黄酮对SD大鼠亲代和F1代生殖发育的影响

目的评价大豆异黄酮(SI)对动物生殖发育的影响。方法 4周龄SD大鼠雌雄各20只。SI组喂饲100mg/kg BW的添加SI的饲料,对照组喂饲普通饲料。检测亲代体重、动情周期、血清激素、精子质量;F1代出生体重及身长、性别比、肛门生殖孔间距、阴道开口和包皮分离时间等。两独立样本t检验比较均数,子代数据以每窝为单位。结果与对照组相比,SI组亲代雌鼠交配前体重和雌雄鼠的食物利用率较低;亲代雄鼠精子总数较高,血清促黄体生成素较低;亲代雌鼠促黄体生成素、催乳素和孕酮的水平较低(以上P<0.05);其他指标在两组中无显著差异。结论 SI对亲代雌鼠交配前的体重、雌雄鼠的食物利用率、精子总数、血清部分激素水平等有影响。     

Organ growth and cellular development in ethanol-exposed rats

Effects of perinatal exposure to ethanol on growth and cellular development were investigated. Alcohol was administered in liquid diets designed to provide optimal nutrition during pregnancy. Pair-fed and ad lib control groups were included. The 3 groups of females were similar in body weight during gestation and lactation, and offspring weights were similar on gestation Day 21 and at birth. By Day 9 of lactation control pups weighted more than both alcohol and pair-fed pups which were similar in body weight. Weights of brain, heart, liver and kidney were reduced in alcohol pups compared to pair-feds and controls. Decreased liver weight reflected both decreased cell size and decreased protein content, but was primarily due to decreased caloric intake. Decreased heart weight appeared to result from a direct effect of ethanol on heart protein content. Even more marked were the adverse effects of ethanol on kidney protein content and kidney DNA (reflecting a decrease in cell number). In contrast, although both absolute brain weight and DNA content were decreased in ethanol-exposed offspring, relative brain weight was increased. Finally, maternal ethanol consumption significantly increased relative placenta weights as well as placental DNA and protein content.     

Effects of prenatal ethanol exposure on iron utilization in the rat

The effects of prenatal ethanol exposure on iron metabolism in rat dams and pups were studied. Sperm-positive nulliparous dams were assigned to groups on the third day of gestation (G3): ET rats were fed a liquid diet containing 9% ethanol (v/v); PC rats were pair-fed a non-ethanol, isocaloric liquid diet; FC rats were fed the same nonethanol diet adlibitum. All animals were individually housed in stainless steel metabolic cages from G3 to G18 and transferred to polypropylene cages to await delivery. Food intake and dam body weight were significantly less in the ET and PC groups compared to the FC control group. Water intake was significantly greater in the ET dams than in controls. Gestation length was significantly increased in the ET rats only. Pup body weight was significantly decreased in the ET rats only compared to controls. Apparent absorption of iron in the ET dams was significantly greater than in the PC and FC dams. The inutero ethanol exposure resulted in a significant increase in liver and femur iron concentrations in the newborn pups when compared to the PC and FC control pups. The marked increase clue to understanding presence of liver pathology that has been reported to occur in children with fetal alcohol syndrome.     

Vitam A deficiency and fetal growth and development in the rat.

Studies were conducted to examine in detail the effects of vitamin A deficiency on fetal growth and development in the rat. The gradations of deficiency were examined in two studies. The first included total vitamin A depletion followed by retinoic acid supplements, and the second included three different levels of restricted intake of retinyl acetate (42, 16, or 8 mug of retinol equivalents/day/kg of body weight) in vitamin A-depleted rats. In the first study, extensive fetal resorption and death were observed in retinoic acid-fed females after day 14 of gestation. These findings confirmed the morphological studies of Thompson and associates (Proc. Roy. Soc. London, Ser. B 159, 510-535, 1964) who found the earliest Detectable histological lesions to be in the placentas at days 15-16 of pregnancy. Analyses were carried out of the total weight, the DNA, RNA, and protein contents of fetuses and placentas of different gestational ages in retinyl ester-fed and retinoic acid-fed females. Biochemical changes indicative of a reduced rate of cell division were observed in both fetus and placenta by day 14 in the retinoic acid-fed rats. The few live fetuses in this group maintained a growth rate of only 60-70% of that of the fetuses of retinyl ester-fed dams after day 14. By contrast, the growth rate of the placentas (of live fetuses) after day 14 of gestation was not as consistently affected by retinol deficiency. Restriction of retinyl acetate intake (in the second study) significantly reduced both the total litter size and the number of live pups per litter. Most of the females in the retinyl acetate-restricted groups delivered pups that had normal body weight and appeared normal on visual inspection. Significant differences from normal controls were seen only in the neonates from dams given 8 mug of retinol equivalents (per kg of body weight per day), which had smaller livers and kidneys than the control neonates. In contrast, the weights of the brains of the neonates in all three retinyl acetate-restricted groups showed no differences from control values. Vitamin A assays on maternal and neonatal sera and livers indicated that the transport of vitamin A across the placenta was well regulated, and suggested that this transport is maintained with high priority in the presence of maternal deficiency. The effects of vitamin A deficiency on fetal growth and development might reflect primary effects on the placenta, with secondary effects on the fetus, or primary direct effects on the fetus itself. The mechanisms of the observed effects remain to be explained.