| Objective: Different diameters of particulate matters lead to different unfavorable impacts on human.10 μm is threshold of the particulate matter’s（PM）diameter which could arrive throat,however,PM2.5 can thread bronchiole into pulmonary alveoli,and turn into whole blood circulation system by blood capillary.PM2.5 is one of main ingredients of air pollutants which has adverse effects on human health and environmental quality,which is related to many kinds of diseases.Our research aims to investigate pregnant mice’s gestation situation,structure change of placenta and oxidative stress of fetus after different concentrations of PM2.5 exposure,and we hope to provide the reference and gist for revealing the reasons and mechanism of adverse pregnancy induced by PM2.5.Methods: This study simulated the constituent of PM2.5 in 2013 winter in Xigu district of Lanzhou City,and we magnified the simulated PM2.5 for 100 folds.The new type of two-stage atomization device was used to nebulize,which was invented by our research group（Authorized invention patent number: 201510016314.5）.Kunming mice as experiment animals were chosen to assess the embryotoxicity of PM2.5 by detecting oxidative stress indexes,histological section and heavy metal detection.32 mice（2832 g）were randomly divided into four groups,including blank group,control group（exposure with distilled water）,low dose group(the exposure concentration of simulated PM2.5 was 7mg/m3)and high dose group(the exposure concentration of simulated PM2.5 was 14mg/m3).Female mouse was mated with male one before exposure,and we confirmed ingravidation by vaginal plug,denoted as embryonic day（ED）0.5,then started exposure at the same day.Exposure period was lasted for 15 days and 6 hours exposure per day.Weight of pregnant mice was recorded,and the situation of drinking water,taking food and behaviour were observed every day.The pregnant mice in ED 16.5 were executed and dissected,and the situation of gestation（implantation number and number of abnormal embryo）was recorded at the same time,at last the placenta and fetus tissues were taken out for detection of the relevant indexes.Results: The results about weight growth situation of pregnant mice,microscopic structure of placenta,observation of fetus and detection of the relevant indexes are as follows.1.Exposure of PM 2.5 led to ponderal growth rate decrease,especially in ED 11.5,the difference was highly significant between exposure groups and blank group（p < 0.01）.2.PM2.5 led to weight reduction and structure abnormal of placenta.All doses of PM2.5 exposure caused to placenta weight reduced highly significantly（p < 0.01）in ED 16.5,however,structure of labyrinth in placenta was changed only in high dose group.3.Effect of PM 2.5 exposure in growth and development of fetus.All dose of PM2.5 exposure not only led to weight of fetus reduced,but also caused by body and tail length of fetus growth rate reduction,meanwhile,non-essential element Pb enrichment was detected in fetus getting through the placenta.4.PM2.5 caused to resorption of embryo.There were not absorbed embryo and malformation embryo phenomenon appearance in blank group and control group,however,1 absorbed embryo in low dose group was observed（the embryo-resorption rate was 0.97%）,and 4 absorbed embryo in high dose group（the embryo-resorption rate was 0.97%）were found.5.PM2.5 exposure accounted for obvious oxidative stress reaction in placenta and fetus.High dose PM2.5 exposure resulted in the content of MDA increasing highly significant（p < 0.01）in placenta and fetus,meanwhile,the T-AOC was decrease highly significant（p < 0.01）.Conclusion:From the above results,this research considered that pregnant mice exposed in high concentration PM2.5 not only influenced their body condition,but also obviously inhibited the development of placenta and fetus and their antioxidant abilities.It illustrated that PM2.5 has the toxic effect on the development of placenta and fetus by pregnant mice’s respiration pathway. |
