Effect of postnatal low-dose exposure to environmental chemicals on the gut microbiome in a rodent model.
This proof-of-principle study examines whether postnatal, low-dose exposure to environmental chemicals modifies the composition of gut microbiome. Three chemicals that are widely used in personal care products-diethyl phthalate (DEP), methylparaben (MPB), triclosan (TCS)-and their mixture (MIX) were administered at doses comparable to human exposure to Sprague-Dawley rats from birth through adulthood. Fecal samples were collected at two time points: postnatal day (PND) 62 (adolescence) and PND 181 (adulthood). The gut microbiome was profiled by 16S ribosomal RNA gene sequencing, taxonomically assigned and assessed for diversity.



Metagenomic profiling revealed that the low-dose chemical exposure resulted in significant changes in the overall bacterial composition, but in adolescent rats only. Specifically, the individual taxon relative abundance for Bacteroidetes (Prevotella) was increased while the relative abundance of Firmicutes (Bacilli) was reduced in all treated rats compared to controls. Increased abundance was observed for Elusimicrobia in DEP and MPB groups, Betaproteobacteria in MPB and MIX groups, and Deltaproteobacteria in TCS group. Surprisingly, these differences diminished by adulthood (PND 181) despite continuous exposure, suggesting that exposure to the environmental chemicals produced a more profound effect on the gut microbiome in adolescents. We also observed a small but consistent reduction in the bodyweight of exposed rats in adolescence, especially with DEP and MPB treatment (p < 0.05), which is consistent with our findings of a reduced Firmicutes/Bacteroidetes ratio at PND 62 in exposed rats.



This study provides initial evidence that postnatal exposure to commonly used environmental chemicals at doses comparable to human exposure is capable of modifying the gut microbiota in adolescent rats; whether these changes lead to downstream health effects requires further investigation.
Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA. jianzhong.hu@mssm.edu.
Jianzhong
J
Hu
Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
Vincent
V
Raikhel
Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
Kalpana
K
Gopalakrishnan
Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
Heriberto
H
Fernandez-Hernandez
Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
Luca
L
Lambertini
Cesare Maltoni Cancer Research Centre, Ramazzini Institute, Bentivoglio, Bologna, Italy.
Fabiana
F
Manservisi
Cesare Maltoni Cancer Research Centre, Ramazzini Institute, Bentivoglio, Bologna, Italy.
Laura
L
Falcioni
Cesare Maltoni Cancer Research Centre, Ramazzini Institute, Bentivoglio, Bologna, Italy.
Luciano
L
Bua
Cesare Maltoni Cancer Research Centre, Ramazzini Institute, Bentivoglio, Bologna, Italy.
Fiorella
F
Belpoggi
Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
Susan
S
L Teitelbaum
Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA. jia.chen@mssm.edu.|Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY, USA. jia.chen@mssm.edu.|Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA. jia.chen@mssm.edu.
Jia
J
Chen
D000818:Animals; D041963:Bacteroidetes / Q000302:isolation & purification; D020562:Betaproteobacteria / Q000302:isolation & purification; D001835:Body Weight / Q000187:drug effects; D020564:Deltaproteobacteria / Q000302:isolation & purification; D004781:Environmental Exposure / Q000009:adverse effects*; D004785:Environmental Pollutants / Q000494:pharmacology*; D004787:Environmental Pollution / Q000009:adverse effects; D005243:Feces / Q000382:microbiology; D005260:Female; D000068536:Bacillota / Q000302:isolation & purification; D000069196:Gastrointestinal Microbiome / Q000187:drug effects*; D010226:Parabens / Q000494:pharmacology*; D010795:Phthalic Acids / Q000494:pharmacology*; D049590:Postpartum Period; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D014260:Triclosan / Q000494:pharmacology*
D004785:Environmental Pollutants; D010226:Parabens; D010795:Phthalic Acids; D012336:RNA, Ribosomal, 16S; D014260:Triclosan; C015358:methylparaben; C007379:diethyl phthalate
Microbiota; Paraben; Phthalate; Triclosan