Toxicity Effects Of Environmental Fine Particulate Matter In Duck Houses On Pregnant Mice

Hazy air particulate matter(PM)contains a large number of microorganisms,heavy metals,organic compounds and other harmful substances,and long-term exposure to high concentrations of air PM can cause harm to human health.Studies have shown that the microbial composition of respirable PM in the livestock farming environment is significantly higher than that in the atmospheric environment,and long-term exposure to high concentrations of microbial aerosols can also harm animal health and even pose a certain threat to the health of farm workers or surrounding residents.To further assess the health effects of fine PM in the farm environment on animals and humans,in this study,we collected samples from the duck houses environment using an airborne PM sampler to inoculate pregnant mice by inhalation to explore the effects of fine PM in the livestock house environment on the reproductive health of mice.The results of the study can provide a scientific basis for assessing the effects of environmental fine PM on organism health on farms,and lay the foundation for an in-depth study of the mechanisms of the effects of fine PM on organism health.In this study,air samples were collected from the housing of a large-scale duck farm in Tai’an City using the ZR-3922 ambient air PM comprehensive sampler,prepared into a certain concentration of PM suspension after centrifugation and vacuum concentration treatment,and nebulized for exposure experiments using an aerosol generator.In this study,Kunming mice were used as experimental animals,and 6-week-old SPF female Kunming mice were randomly divided into three groups of 20 mice each,namely mock group(MG,normal feeding),low concentration group(LCG,0.48 mg/m~3),and high concentration group(HCG,1.92 mg/m~3),which were freely mated with SPF male mice after a 7-day acclimation period,and the date of first observation of vaginal plugs was defined as gestation day 0.5days of gestation.Pregnant mice were exposed to daily aerosolization using an aerosol generator for 6 h each time starting from day 5 of gestation,and exposure continued until day 20 of gestation(day 15 after exposure)or spontaneous delivery(generally 21 days for spontaneous delivery).The food intake,water consumption and mental status of the pregnant mice were recorded daily during the experiment.To evaluate the effects of duck houses particulate matter exposure on the health and reproduction of pregnant mice,10 pregnant mice were randomly dissected in each group on day 20 of gestation(day 15 after exposure),pregnancy was recorded,dissected lesions were observed,and tissues or organs such as lungs and placentas were collected for histopathological analysis,and tissue inflammatory factors and oxidative stress levels were measured.The results showed that PM exposure slowed down the weight gain of pregnant mice and caused lesions in the lungs and placenta,with varying degrees of interstitial lung widening and inflammatory cell infiltration in the lungs and structural abnormalities in the placenta,especially edema in the meconium layer and ischemia in the vagus region in the HCG.Compared with the MG,PM exposure in the HCG significantly increased the inflammatory factors in the lungs and placentas of pregnant mice,with the upregulation of TNF-αin the placenta being 43.96 times higher than that in the MG and the upregulation of CCL5 in the lungs being 33.75 times higher than that in the MG.In addition,PM exposure caused oxidative stress in the blood of pregnant mice and resulted in a 1.14-fold and significant(P<0.01 or P<0.05)decrease in blood estrogen levels.Assessment of the effects of fine particulate matter in duck houses on pregnant mice and the pups they give rise to,this experiment measured the body weight and body length of the newborn pups in each group of remaining pregnant mice after natural delivery,and collected the brains and livers of the pups,which were also subjected to histopathological changes,inflammatory factor levels,and oxidative stress levels.It was found that the HCG and LCG resulted in a reduction in the number of pregnant litters and a significant reduction in the body length and tail length(P<0.01)and weight(P<0.01)of the delivered fetuses in pregnant mice compared to the MG.This trend was positively correlated with the concentration of PM exposure.In addition,high concentration exposure resulted in a 3.92-fold increase in IL-6 in the brains of the pups compared to the MG,with significantly lower expression of IL-4,IL-10,IFN-γ,and GABA-A,a neurotrophic factor,in the HCG(P<0.05).PM exposure also led to oxidative stress in the brains of newborn mice and was significantly different from the MG(P<0.01).In summary,higher concentrations of duck houses PM exposed to pregnant mice by inhalation not only cause significant inflammatory responses and oxidative stress in pregnant mice themselves,but also affect their reproductive system,causing a reduction in litter size,oxidative stress and developmental delay in newborn pups.