| BackgroundIntestinal Microorganism has been shown to be highly involved in many important physiological processes critical to human health.Many factors can affect the composition and function of gut microbiota,and the complex interactions between environmental pollutants and microbiota have been poorly studied.As a chlorinated flame retardant,DP was a kind of global organic pollutant.Although the biological accumulation of DP has been discussed in many studies,there was few study on the intergenerational transmission of DP and its relationship with gut microbiota of organisms.ObjectiveThe purpose of this study was to explore the biological accumulation and intergenerational transmission of DP in pregnant rats and their influence on the structure and function of gut microbiota to their offspring through 16S rRNA gene amplicome sequencing.To evaluate the role and mechanism of DP in regulating intestinal function.Methods1.Male and female SD rats were caged together to create A model of pregnant rat.The exposed groups were given 5 mg/kg/d DP dissolved in corn oil by intragastric administration from the beginning of pregnancy to the end of pregnancy(group B)or the end of lactation(group C),and the control group(group A)was given equal amount of corn oil by intragastric administration.The feces of female rats was collected during pregnancy,lactation and offspring’s childhood and adulthood,and the liver and serum were dissected from female rats and offspring for subsequent analysis.2.Collected feces and liver samples for pretreatment.The concentration of DP in different samples was detected by gas chromatography-mass spectrometry(GC-MS),and its bioaccumulation ability and intergenerational transmission in maternal and offspring tissues were analyzed.3.The collected feces were subjected to DNA extraction,PCR amplification and purification.The V4 variable region of 16S rRNA gene was detected by Illumina high-throughput sequencing,and the intestinal flora was analyzed by QIIME.GC-MS was used to detect the concentration of short chain fatty acids(SCFAs)in feces,and the changes of intestinal flora and their effects on SCFAs in SD rats after DP exposure were analyzed.Results1.Compared with liver and serum,the concentration of ∑DP in feces was higher.The highest concentration of ∑DP in the feces was 183 ± 107 μg/g dw during pregnancy of exposed group C.In the liver,there was a significant difference in the DP concentration between group C and group B during pregnancy and immature offspring(P<0.05).In serum,DP was not detected in the serum of the offspring of group B,while lower DP concentrations was detected in the serum of the offspring of group C.The ratio of exposure to the concentration of DP in the liver/serum(L/S ratio)is much larger than one unit.2.The diversity indexes of Ace,Chao1,Shannon and Simpson in the exposed groups and their offspring all showed a downward trend,and the species diversity decreased.At the level of phylum,the abundance of Bacteroidetes decreased slightly from pregnancy to lactation.At the level of family,the species abundance of the exposed group decreased from pregnancy to lactation and offspring compared with the control group.On the genus level,compared with the control group,the dominant bacteria in rats during pregnancy changed from Prevotella,Lactobacillus and Streptococcus to Bacteroides,A kkermansia and Erysipelatoclostridium.3.The SCFAs in feces was mainly composed of acetic acid,propionic acid and butyric acid.The proportion of isobutyric acid during pregnancy and lactation in group C increased by 42%and 26%,respectively.Compared with the control group,the acetic acid concentration in pregnant rats and offspring in exposure group increased significantly(p<0.01),and the highest acetic acid concentration in lactating pregnant rats in exposure group C was 0.78±0.08 μg/g.The concentration of propionic acid in the exposed group during lactation and offspring was significantly higher than that in the control group(p<0.05),and the highest concentration of propionic acid in the exposed group B was 0.1 8± 0.09 μg/g.Similarly,in the pregnant rats and offspring of the exposed group,the concentration of butyric acid in feces was significantly higher than that in the control group(p<0.05),while the highest concentration of butyric acid in immature offspring of exposed group was 0.13 ± 0.01 μg/g.The highest concentration of isovaleric acid in group C was 0.068 ±0.002 μg/g.Conclusion1.Most of DP was excreted through feces,but less was absorbed by tissues;From childhood to adulthood,the DP concentration of offspring of group B was almost undetectable,while that of group C was relatively low,indicating that DP may be passed to the next generation through breast milk.DP was preferentially accumulated in the liver relative to serum in rats.2.The species diversity and abundance of immature and adult offspring decreased after exposure to DP during pregnancy and lactation in rats.3.The concentrations of acetic acid,propionic acid,butyric acid and iso-valeric acid in group C were significantly higher than those in group B and control group,and long-term exposure to DP could affect the level of SCFAs in the feces of female rats and their offspring. |
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