Associations of air PM2.5 level with gut microbiota in Chinese Han preschoolers and effect modification by oxytocin receptor gene polymorphism

Variations in the single nucleotide polymorphisms (SNPs) of the oxytocin receptors (OXTR) indicate individual differences in stress response, social behavior, and psychopathology, but very few paper mentioned OXTR as part of the mechanism linking exposure to air pollution and poor social interactions. The authors investigated the moderating role of Oxytocin receptor (OXTR) rs53576 polymorphism in the relationship between PM2.5 level and gut microbiota in children, in an attempt to provide some reference for the evidence linking biological and environmental factors to children brain development. The study included 86 healthy Chinese preschoolers (50 males, 36 females) from two campuses of a kindergarten with different air PM2.5 levels. Atmospheric PM2.5 values released by air quality monitoring stations where the two campuses are located were collected for 30 days. The genotypes of OXTR rs53576 were determined by PCR and restriction fragment length polymorphism. The gut microbiota situation was evaluated by determining urinary concentrations of short-chain fatty acids. Urinary levels of cortisone and cortisol were determined to assess the impact of air pollution on the HPA axis. Urinary 2′-Deoxy-7,8-dihydro-8-oxoguanosine and 8-oxo-7,8-dihydroguanosine were measured to evaluate the oxidative stress state. The genotype distribution frequency of rs53576 polymorphism was consistent with Hardy-Weinberg equilibrium. The average urinary concentrations of cortisone, cortisol and 8-OHdG in high pollution campus preschoolers were significantly higher than those in low pollution campus preschoolers, while situations were opposite for acetic acid, propionic acid, isobutyric acid, butyric acid and valeric acid. The interaction between OXTR rs53576 and air pollution had a significant effect on urinary acetic acid. Allele G of rs53576 may be a risk factor for gut microbiota disorder caused by air pollution, and children with GA/GG genotype may be more susceptible than those with AA genotype.