Effect Of The Prenatal Exposure To Polycyclic Aromatic Hydrocarbons (PAHs) On The Neonatal Neurodevelopment And The DNA Telomere Length In Umbilical Cord Blood

Objective To explore the effect of prenatal Polycyclic Aromatic Hydrocarbons (PAHs)exposure on neonatal neurodevelopment and the telomere length in umbilical cordblood.Methods106pairs mothers and their neonates were recruited in this study fromNovember2009to April2010. General information of mothers was obtained byquestionnaire. PAHs metabolites in urine were used as biomarkers of individualsexposure to PAHs,which were measured by SPE-HPLC Fluorescent Assay; Neonateneurobehavioral developmental levels were assessed by Neonatal BehavioralNeurological Assessment (NBNA); Real-time quantitative PCR was used to measurethe telomere length in cord blood; SPSS16.0statistical software was utilized toanalyze data.Results1. PAHs metabolites: The creatinine-adjusted concentrations for2-Naphthol,2-Hydroxyfluorene,9-Phenanthrol,1-Hydroxypyrene were3.7（33.17-4.39）μg/g Cr,1.08（0.89-1.31）μg/g Cr,0.72（0.59-0.89）μg/g Cr,0.24（0.20-0.30）μg/g Cr,respectively.2. Characteristics of the study population by PAHs exposure: The study populationwere separated into low exposure group and the high exposure group according toPAHs metabolites sum P75:10.21ug/g Cr, in order to compare their normalcircumstances. There were no significant statistical differences between high-andlow-exposure groups in maternal education, family income, newborns areas andother exposure situations.3. NBNA scores: On average, the low exposure group is1.1points higher than thehigh exposure group on NBNA scores. By the Wilcoxon rank sum test, thedifference was statistically significant (Z=-1.161, P <0.001).4. The correlation between PAHs exposure and NBNA: In the Spearman rankcorrelation analysis, PAHs hydroxy metabolites showed a weak negativecorrelation with NBNA scores (rs=-0.200, P=0.039), which means the higher PAHs exposure during pregnancy, the lower NBNA scores. The analysis result ofNBNA scores by stepwise multiple linear regression analysis method is pregnantmothers hydroxy metabolites in urine PAHs sum (logarithmic) partial regressioncoefficient β=-0.27(95%CI:-1.42,-0.24; P=0.006), which indicated that PAHshydroxy metabolite concentration increased by10times the sum, ceteris paribus,NBNA score would be0.27points lower.5. Comparison of telomere length: It is found that low exposure group relative TL was1.06±0.31, the high exposure group was0.83±0.44.In high exposure group, therelative telomere length was shortened by about21.7%compared with the lowexposure group.6. The correlation between PAHs exposure and telomere length: In all subjects (n=106), the exposure levels and telomere length in the Spearman correlation analysisconducted PAHs, rs=-0.206, P=0.034, which explained PAHs hydroxy metabolitelevels relative telomere length was inversely correlated. In other words, with thelevel of PAHs exposure increasing, the telomere length was shortening.7. The correlation between telomere length and NBNA scores: By respectively usingmedian of telomere length (1.00) and NBNA(39score) as a cut-off value, it isfound that the telomere length had a weak correlation with NBNA(χ2=4.566, P=0.033).Conclusion1. PAHs exposure during pregnancy lowered neonatal NBNA score;2. PAHs exposure during pregnancy shortened telomere length in the cord bloodlymphocyte.