【作者】 李辉；

【导师】 王志萍；

【作者基本信息】 山东大学 ， 流行病与卫生统计学， 2009， 硕士

【摘要】 研究背景近年来,随着人们生活水平的提高,居室装修成为时尚。新婚夫妇多选择在新居装修后入住,由居室装修所造成的室内污染是否对新婚夫妇的生育健康造成不良影响已引起社会的广泛关注。监测资料显示,装修后室内环境中存在多种污染物,其种类和浓度随着装修材料的品种、家具数量、装修程度以及装修后入住时间不同而存在较大差异。这些多种类、多水平、动态变化的暴露方式给评价其生殖毒性带来一定难度,目前尚缺乏对这种暴露模式与生殖毒性关系的研究报道。苯与甲醛是房屋装修后最常见的两种室内污染物。以往研究表明,苯或甲醛单独存在时对女性的月经周期和生殖机能具有明显影响;动物实验显示两者单一染毒均可产生明显的母体毒性,并引起染毒动物胚胎发育障碍,或产生明显的致畸性。已有研究多采用将雌鼠孕前暴露的染毒方式,观察实验动物单独暴露于苯或甲醛时的生殖和发育毒性或致畸性,而胚胎植入期暴露于苯或甲醛对胚胎植入和胚胎早期发育的影响研究较少,尤其是两者混合存在时其生殖毒性是否存在交互作用未见文献报道。本研究选择居室装修后室内常见的两种污染物苯和甲醛作为指示物,采用析因设计模拟两种污染物不同剂量水平复杂存在现状,探讨围植入期暴露于苯和甲醛对小鼠胚胎植入和早期胚胎发育的影响。研究目的观察胚胎围植入期暴露于不同水平的苯和甲醛是否具有胚胎毒性,比较不同植入时段暴露于苯和甲醛后其胚胎毒性差异;将胚胎的围植入期分为三个时段:胚胎植入前期、胚胎植入期和胚胎植入后期,探讨两者胚胎毒性的敏感毒作用位点;测定孕鼠血清中促黄体生成素（LH）、雌二醇（E₂）和孕酮（P₄）三种激素水平,进一步探讨胚胎植入障碍与母体血清激素含量之间的关系,为居室装修后室内污染物生殖毒性评价提供理论依据。研究方法设计三种暴露时期:胚胎植入前期、胚胎植入期和胚胎植入后期;苯与甲醛两种暴露因素,各设4个剂量水平,分别为（0,0.875,8.75,87.5）mg/kg和（0,7.875,15.75,31.5）mg/kg。采用两因素四水平析因设计安排苯与甲醛暴露的剂量组合,每个暴露时期中两种因素共构成16种剂量组合,共48个实验组。按上述析因设计的剂量组合实验重复4次,共有192只孕鼠。雌鼠与雄鼠1:1合笼,次日查到阴栓为孕1 d,按体重随机分配统一编号。按照设计的胚胎植入暴露时段经腹腔染毒,1次/d,连续3d。孕第9d收集静脉血后脱臼处死,子宫、卵巢及肝、脾、肾等脏器称重;计数每个子宫角胚胎植入数目并称取胚胎、子宫重量。采用ELISA方法测定小鼠血清中LH、E₂和P₄的含量。SPSS13.0建立数据库并分析数据。研究结果1.胚胎植入与早期发育障碍1.1.1.1单一暴露时苯或甲醛的单独作用母体毒性:胚胎植入期暴露,苯减轻孕鼠脾脏重量（P=0.012）;胚胎植入后期暴露,苯能够降低孕鼠肝脏重量（P=0.012）;但植入前期暴露未观察到明显的母体毒性。上述三个暴露期均未见甲醛致母体毒性作用。说明围植入期三个时段苯或甲醛单一暴露仅产生轻微的母体毒性。胚胎毒性:胚胎植入前期暴露,苯和甲醛均可减少小鼠胚胎植入数目（P值分别为0.024和0.004）,降低其胚胎总重量（P值分别为0.019和0.002）和胚胎平均重量（P值分别为0.024和0.002）;胚胎植入期暴露,甲醛可明显减少胚胎植入数目（P=0.036）,未见苯对胚胎植入数目的影响;两者对胚胎总重量和胚胎平均重量均无明显影响;胚胎植入后暴露,未发现两者对胚胎植入数目、胚胎总重量和胚胎平均重量的影响。1.2.共同暴露时苯和甲醛的主作用胚胎植入前期共同暴露于苯和甲醛:甲醛可明显减少小鼠胚胎植入数目（P=0.005）,降低胚胎总重量（P=0.008）;苯仅对小鼠胚胎平均重量产生一定影响（P=0.009）。胚胎植入期暴露:两者对胚胎植入数目、胚胎总重量和胚胎平均重量均无明显影响。植入后暴露:甲醛可减轻小鼠胚胎平均重量（P=0.042）。2.小鼠血清激素水平2.1暴露于苯和甲醛对三种激素的影响苯和甲醛共同暴露对激素影响的联合作用:胚胎植入前期暴露,苯明显降低小鼠血清E₂水平（P=0.048）;植入期暴露于苯激素水平变化不明显;植入后期暴露,苯明显降低小鼠血清P₄水平（P=0.039）;甲醛对小鼠血清激素含量影响没有统计学意义。2.2胚胎植入障碍与小鼠血清激素水平之间的关联性胚胎植入前期暴露,苯所致胚胎植入障碍与小鼠血清E₂和P₄水平之间关联性具有统计学意义（P值分别为0.041和0.043）:植入期暴露,苯所致胚胎植入障碍与小鼠血清LH水平相关联（P=0.045）;植入后暴露,苯所致胚胎植入障碍与小鼠血清P₄水平之间相关性具有统计学意义（P=0.038）。胚胎围植入期甲醛暴露所致胚胎植入障碍以及与胚胎正常植入组小鼠血清中LH、E₂和P₄水平之间均无明显关联性。结论1.小鼠胚胎围植入期暴露于苯或甲醛均可导产生明显的胚胎毒性;甲醛胚胎毒性较高。2.小鼠胚胎植入前期暴露于苯和甲醛,其胚胎毒性较胚胎植入期和植入后期更为敏感。3.低剂量苯或甲醛暴露可致小鼠产生明显的胚胎毒性;苯或甲醛不同暴露水平之间胚胎毒性作用不同,胚胎毒性表现出一定的剂量依赖性。4.苯暴露影响孕鼠血清激素含量,可能是苯致胚胎植入障碍的重要原因之一。甲醛暴露其胚胎毒性与母体激素水平之间无明显关联。更多还原

【Abstract】 BackgroundWith the development of people’s living standard, it is becoming more and more popular to have house decorated before living in, especially for the young couples. The doubt that whether the pollution after house decoration could do harm to the healthy of reproducitivity was widely concerned. Surveillance data showed that contaminants in the atmospheres of house after family decoration were dominant and different due to the difference of decorating materials, the numbers of furniture and the time after decoration. The complicated exposure model brought great difficulty to the evaluation of the exposure model, so there were only a few studies which focused on the evaluation of the contaminants. Benzene （BZ） and formaldehyde （FA） are among the most common contaminants after family decoration. Previous studies indicated that exposure to BZ or FA alone could obviously affect the menstrual cycles and reproductive function. Animal experiments showed that exposure to BZ or FA could lead to maternal toxicity and the developmental disabilities of embryos. However, the time for exposure in previous study was usually before mating. There were few studies focused on the effect on the implantation and early development of the contaminant. BZ and FA were selected to be the representatives in newly decorated house to explore the toxicity on the implantation and early development of embryos in mice.ObjectiveThe pregnant mice were exposed to BZ and/or FA at stages peri-implantation: pre-implantation, implantation and post-implantation, in order to explore the sensitive point of the embryotoxicity by BZ and/or FA and provide advices for evaluating the reproductive toxicity of the indoor contaminants; the serum reproductive hormones, including LH, E₂ and P₄ were detected at the three stages of implantation in order to illustrate the relationship between embryo implantation and the concentration of the reproductive hormones in serum.MethodsThe factorial design was applied to observe the maternal and embryo toxicity after exposure to BZ and/or FA. There are three stages, including pre-implantation, implantation and post-implantation. There were four dosages for both BZ （0, 0.875, 8.75 and 87.5 mg/kg） and FA （0, 7.875, 15.75 and 31.5 mg/kg）. After ovulation induction, the pregnant mice were exposed to the chemicals by intraperitoneal injection. 4×4 factorial design was used to arrange the exposed dosage combinations of BZ and FA. Each exposed stage includes 16 dosage combinations by 2 factors. And so three stages and 4×4 factors make up of 48 experiment groups. Each dosage combination is repeated for 4 times. Males and females were placed 1:1 overnight to impregnate and assessed for the presence of a vaginal plug in the next morning. Plugged females designated day 1 of pregnancy. They were divided randomly grouping based on their weights. The mice were exposed BZ and FA via intraperitoneal injection during the phases of implantation, once per day, for successive 3 days. The pregnant mice were killed by cervical dislocation after harvested venous blood on the GD9. The uterus, ovaries, embryos, placenta, livers, spleens and kidneys were weighted. The implanted embryos in each uterine horn were numerated. The detection of the reproductive hormones （LH, E₂, P₄） followed the instructions of the ELISA kit. Results were analyzed by a computerized statistical program （SPSS 13.0）.Results1. Establishment of animal model1.1 Effects of exposure to BZ or FA alone:Both BZ and FA had only slight maternal toxicity at all the three exposure stages. When exposed to BZ alone, the difference on the weight of spleens among groups was statistically significant at the stage of implantation （P=0.012）; while at the stage of post-implantation, the difference on the weight of kidney among groups was statistically significant （P=0.012）.Embryotoxicity: Both BZ and FA had obvious embryo toxicity at the stage of pre-implantation. Both of them had obvious toxic effect on the number （P was 0.024 for BZ and 0.004 for FA）, total weight （P was 0.019 for BZ and 0.002 for FA） and mean weight （P was 0.024 for BZ and 0.002 for FA） of embryos at the stage of pre-implantation. No similar results were observed at the stage of implantation and post-implantation.1.2 Main effects of BZ and FA:When BZ and FA were exposed to the mice in combination at the phase of pre-implantation, FA had obvious impact on the number （P=0.005）, total weight of the embryos （P=0.008）; while BZ only have effect on the mean weight of embryos. At the stage of implantation, neither BZ nor FA had impact on the number, total weight and mean weight of the embryos. At the stage of post-implantation, only FA had effect on the mean weight of the embryos （P=0.042）.2. Effect on the concentration of reproductive hormones in serum2.1 The effect on serum reproductive hormonesThe serum E2 concentration levels were statistically different at different doses of BZ when the mice were exposed to BZ and FA at the stage of pre-implantation （P=0.048）; while the serum P₄ concentration was affected by the exposure at the stage of implantation （P=0.039）.2.2 The relation between implantation disabilities and levels of the hormonesThe serum E₂ and P₄ levels of mice in implantation disabilities group were affected by BZ exposure at the phase of pre-implantation （P was 0.041 and 0.043）; the LH concentration levels of mice in implantation disabilities group were affected by BZ exposure at the phase of implantation （P=0.045）; the P₄ levels of mice in implantation disabilities group were affected by BZ exposure at the phase of post-implantation （P=0.038）. Both BZ and FA had no effect on the concentration levels of serum LH, E₂ and P₄ of mice in embryo group at the three phases.Conclusion 1. Exposure to BZ or FA could result in the decreasing of implantation number, total and mean weight of embryos. So both BZ and FA could produce embryotoxicity. The embryotoxicity of BZ was more obvious when compared with same levels of FA.2. The embryotoxicity of the pregnant mice exposed to BZ and FA was more obvious at pre-implantation compared with the other two phases.3. Both BZ and FA had obvious embryotoxicity at their low dosages （0.875mg/kg of BZ; 7.875mg/kg FA）.4. Exposure to BZ could affect the concentration of hormones in the pregnant mice, which might be one of the factors affecting the implantation of embryos.更多还原