Effects Of Pesticides Exposure On Female Fertility And Infants' Neurodevelopment

Organophosphate pesticides(OPs)and pyrethroid pesticides(PYRs)are the most widely used pesticides in China.Numerous studies have suggested the widespread OPs and PYRs exposures in general population in China,however related studies of OPs and PYRs exposure have only focused on the potential health effects of single pesticide exposure.Considering the mixed use of OPs and PYRs in our country,it is important to explore the effects of OPs exposure,PYRs exposure,as well as their interactions on human health,especially in susceptible people such as women and children.Up to now,only a few epidemiological studies has explored the impacts of OPs and PYRs exposure on female fertility and most published studies have assessed pesticide exposures through questionnaires.To the best of our knowledge,no study has reported the associations between quantitatively measured pesticide exposures and female fertility.In addition,although OPs and PYRs are known as neurotoxicants,little is known about the effects of prenatal OPs and PYRs exposures on infants' neurodevelopment,especially most studies were from developed countries and the results were ambiguous.Since prenatal period is critical for infants' neurodevelopment,it is necessary to assess the effects of prenatal OPs and PYRs exposure and their interactions on infants' neurodevelopment.Because of the high fecundity,in vitro fertilization and transparency during early life stages,zebrafish has been widely used in neuroscience toxicology study as a new animal model.Metabolomics is a new omics technology with strong application prospect in toxic effects study of long-term low-dose environmental pollutants exposure.Metabolomics changes in zebrafish caused by low doses of OPs and PYRs exposures may provide new clues for their neurotoxicities.Section one.The effects of pesticides exposure on female fertilityBackground: Animal experiments have indicated the adverse effects of OPs and PYRs exposure on female reproductive functions,but limited epidemiological studies has explored the associations between OPs and PYRs exposure on female fertility.So far,none of these published studies have examined the effects on female fertility with quantitatively measurement of pesticide exposures.Objective: To investigate the effects of OPs exposure,PYRs exposure,as well as their potential interactions on female menstruation,time-to-pregnancy(TTP)and infertility.Methods: Preconception women who prepared for pregnancy were recruited into the Shanghai Birth Cohort.Urine sample were collected to assess pesticide exposures by measuring urinary metabolites of OPs and PYRs.Menstrual conditions were obtained through questionnaire.TTP and infertility were prospectively collected through 1 year telephone follow-up.Results: A total of 615 women were included in the present study.The detection rates of major urinary metabolites of OPs and PYRs were above 90%,including OPs metabolites dimethylphosphate(DMP)as 94.1%,dimethylthiophosphate(DMTP)as 93.0%,diethylphosphate(DEP)as 99.8%,diethylthiophosphate(DETP)as 100% and PYRs metabolite 3-phenoxybenzoic acid(3PBA)as 99.0%.In terms of menstruation,DMTP [OR = 1.64,95%CI:(1.10,2.44),P = 0.015] and DEP [OR = 2.00,95%CI:(1.10,3.53),P = 0.017] were associated with an increased risk of irregular menstruation;DMTP [OR = 1.59,95%CI:(1.00,2.52),P = 0.050] was associated with an increased risk of abnormal amount of menstrual bleeding;DMP [? =-0.16,95%CI:(-0.29,-0.03),P = 0.015],DMTP [? =-0.27,95%CI:(-0.43,-0.11),P = 0.001],DEP [? =-0.25,95%CI:(-0.47,-0.03),P = 0.023] and DETP [? =-0.34,95%CI:(-0.56,-0.11),P = 0.003] were negatively associated with the menstrual bleeding duration.In terms of TTP and infertility,women with the highest quartile of DETP(Q4)were significantly associated with longer TTP [FOR = 0.68,95%CI:(0.51,0.92),P = 0.012] and increased risk for infertility [OR = 2.17,95%CI:(1.19,3.93),P = 0.011] compared with women with the lowest quartile of DETP(Q1).In nulliparous women,women with the highest quartile of 3PBA(Q4)were related to longer TTP [FOR = 0.72,95%CI:(0.53,0.98),P = 0.034] and increased risk of infertility [OR = 2.03,95%CI:(1.10 to 3.74),P = 0.023] in comparison with women with the lowest quartile of 3PBA(Q1).In addition,we found significant interactive effects between DETP and 3PBA in female dysmenorrhea with the relative excess risk due to interaction(RERI)as 0.83(95%CI: 0.29,1.38)and the attributable proportion due to interaction(AP)as 0.68(95%CI: 028,1.08).Conclusions: Preconceptional OPs and PYRs exposures could affect female fertility,showing as significantly increased risks of irregular menstruation and abnormal amount menstrual bleeding,reduced menstrual bleeding duration,as well as longer TTP and high risk of infertility.Besides,DETP and 3PBA had significant interactive effects in female dysmenorrheal.Considering the limited epidemiological studies in related filed,more studies are needed to confirm our findings.Section two.The effects of prenatal pesticides exposure on infants' neurodevelopmentBackground: Animal studies have indicated prenatal OPs or PYRs exposure could impair offsprings' neurodevelopment,however in epidemiological studies,the effects prenatal OPs and PYRs exposures on infants' neurodevelopment were still inconsistent and most of those studies were from developed countries.Objective: To explore the effects of OPs exposure,PYRs exposure,as well as their potential interactions on infants' neurodevelopment at age of 1 year old.Methods: This investigation is based on the Laizhou Wan Birth Cohort(LWBC).Pregnant women were recruited in their third trimester of pregnancy and urine samples were measured to detect the urinary metabolites of OPs and PYRs.We prospectively followed up their infants and assessed their neurodevelopment at age of 1 year old using the Gesell developmental schedules(Gesell).Results: A total of 379 pregnant women who detected the urinary metabolites of both OPs and PYRs were included in the present study.Among them,289 infants assessed their neurodevelopment at age of 1 year old.The detection rates of major urinary metabolites of OPs and PYRs in 379 pregnant women were above 85%,including DMP(94.5%),DMTP(85.2%),DEP(98.7%),DETP(98.2%)and 3PBA(94.5%).After adjustment for potential confounders,we found a significant negative association between DEP and adaptive domain developmental quotient(DQ)[? =-1.93,95%CI:(-3.39,-0.47),P = 0.010].After stratified by gender,we found significant negative associations between DEP [? =-4.47,95% CI:(-7.64,-1.30),P = 0.006],DETP [? =-3.66,95% CI:(-7.27,-0.05),P = 0.047] and gross motor domain DQ,DEP [? =-3.65,95%CI:(-5.72,-1.59),P=0.001],DETP [? =-2.78,95%CI:(-5.15,-0.41),P=0.022],DAPs [? =-2.21,95%CI:(-4.63,-0.05),P=0.045] and adaptive domain DQ in girls;Although no association was found between OPs or PYRs exposure and infants' neurodevelopment in boys,we noticed that a significant interactive effect between DETP and 3PBA in fine motor domains in boys [? =-8.98,95% CI:(-17.81,-0.15),P = 0.046].Conclusions: Our results suggested that prenatal OPs and PYRs exposure could affect the adaptive domains of infants at age of 1 year old.After stratified by gender,there was significant interactive effect between DETP and 3PBA in fine motor domains in boys.Section three.The neurobehavioral toxicities and metabolomics changes of pesticides exposure on zebrafish embryonsBackground: Although the neurotoxic mechanisms of acute OPs and PYRs poisoning have been well understood,the neurotoxicities and their mechanisms of long-term low-dose of OPs and PYRs exposures remain unclear.Objective: To observe the neurobehaviors and non-targeted metabolomics changes of zebrafish larvae after low level combined exposures of OPs and PYRs in zebrafish embryos.Methods: Chlorpyrifos and deltamethrin were selected as the representative pesticides for OPs and PYRs respectively in the present study.We observed the developmental and neurobehavioral toxicities in zebrafish then conducted non-targeted metabolomics analysis.Results: Low-level chlorpyrifos and deltamethrin exposure could cause developmental toxicities of zebrafish embryos,including death,deformity and hatching delay.In terms of neurobehavior,chlorpyrifos and deltamethrin could induce decreased equilibrium ability,reduced larvae swimming movement speed and distances,as well as weaken light-evoked startle escape response activity(P < 0.05).When compared with the solvent control group,significant metabolites changes in non-targeted metabolomics detection of chlorpyrifos and deltamethrin exposures were observed(P < 0.05),mainly including phospholipid metabolism and amino acid metabolism,such as lecithin,cephalin,L-glutamine,L-ornithine and cysteine which may related to infants' neurodevelopment.In addition,we found that the combined exposure of chlorpyrifos and deltamethrin had synergistic effects on zebrafish developmental and neurobehavioral damages when compared to their corresponding single pesticide exposure.Conclusions: Our results suggested that chlorpyrifos and deltamethrin had neurobehavioral toxicities and could cause metabolomics changes that associated with neurodevelopment in zebrafish.Besides,the chlorpyrifos and deltamethrin had synergistic effects on neurobehavioral damages in zebrafish.The metabolites we found in the present study may provide some potential biomarkers for the neurotoxic mechanisms of long-term low-dose chlorpyrifos and deltamethrin exposure,but further experiments are needed to verify our results.