Comparison of Gut Microbiota and Toll-Like Receptor 2 and 4 (TLR2/4) Gene Expression in Young Adult Mice Conceived by Natural Pregnancy or Assisted Reproductive Technologies (ART)

Research on determination of microbiota diversity in health and disease continue intensively. Individuals conceived through assisted reproductive technologies may experience various health risks later in life. Here, we investigated whether in vitro embryo culture and embryo transfer would alter the cecal microbiota and the Toll-like receptor 2 (TLR2) and TLR4 profile of mice in the postnatal period. Samples of cecal contents and colon tissue were collected from offspring conceived by in vitro embryo culture and embryo transfer (experimental group, EG) or born through natural pregnancy (control group, CG) at 15 weeks of age. The 16S rRNA gene’s V1–V8 regions were sequenced to determine bacterial taxonomy. TLR2 and TLR4 were determined using quantitative real time polymerase chain reaction (qRT-PCR) and western blotting methods. Results indicated that the EG had a lower proportion of Bacteriotedes (p < 0.05). Also, the ratio of Firmucutes to Bacteriodetes was significantly higher in the EG (p < 0.05). Additionally, at the species level, there was a greater proportion of Helicobacter ganmani in the EG (p < 0.05). The EG exhibited a 1.66-fold increase (p < 0.05) in TLR2 mRNA expression level, while TLR4 expression level showed no difference. Our data are the first to show that cecal microbiota and TLR2 expressions are different in mice conceived by in vitro embryo culture and embryo transfer compared with the offspring born through natural pregnancy. It is also noteworthy that the changes in the microbiota at the phylum level in the EG are consistent with dysbiosis in some diseases such as diabetes and obesity.