Modulation of gut microbiota composition due to early weaning stress induces

It has been shown that early weaning induce various developmental effects and the early-weaned mice (EW mice) show increased anxiety, the enhancement of the stress response of hypothalamic-pituitary-adrenal (HPA) axis, and reduced maternal behavior in their adulthood. It has also known that early life stress including early weaning impacts the immune system and therefore increases vulnerability to infection. Interestingly, offspring of the EW mice shows the enhanced stress response of HPA axis and behavioral changes similarly with the EW mice. In addition, many studies has recently reported that composition of gut microbiota at juvenile period affects the development of both the nervous and immune system. Here, we hypothesized that early weaning modulates the gut microbiota composition and then affects the development of the nerve and/or immune system. For the purpose of clarifying this hypothesis, we analyzed behavioral phenotypes and immune profiles of germ free mice colonized with gut microbiota of EW mice.