A preliminary study of fecal microbiota transplantation alleviating inhibition of radiation-induced hippocampal neurogenesis in mice / 中华放射肿瘤学杂志

ABSTRACT

Objective:To evaluate the effects of whole brain irradiation (WBI) and fecal microbiota transplantation (FMT) on hippocampal neurogenesis and the composition of gut microbiota in mice.Methods:Forty specific pathogen free ICR male mice (8-week-old, weighed 30 g) were divided into four groups by simple random sample method: control group (group C), radiation group (group R), group C+FMT and group R+FMT, 10 in each group. Animal models were established by WBI at a dose of 10 Gy by 4 MeV electron beam. In group C+FMT and group R+FMT, mice were gavaged with normal fecal bacteria suspension on day 2 post-irradiation, while those in group C and group R were gavaged with phosphate buffered saline as alternative. Hippocampal tissues and feces in four groups were collected on day 15 post-irradiation. 16S rRNA sequencing was used to detect the species and abundance of fecal flora. BrdU +/NeuN + immunofluorescence staining was performed to observe the neurogenesis in hippocampus of mice. Results:WBI and FMT had no effect on survival rate and body weight of mice. WBI induced the inhibition of hippocampal neurogenesis and flora disorder. The quantity of Bacteroideae and Rumen bacteria was increased by 28.6% and 102.9%, whereas that of Lactobacillus was significantly decreased by 70.6% ( P<0.05). FMT regulated the abundance of bacteria. The abundance of Enterobacteriaceae was significantly declined by 65.1% ( P=0.028), while that of Lactobacillus was increased by 58.2% ( P=0.015). FMT also promoted hippocampal neurogenesis to some extent after WBI. Conclusions:This preliminary study demonstrates that FMT alleviates the inhibition of hippocampal neurogenesis and flora disorder induced by WBI in mice. Ionizing radiation directly acting on the whole brain of mice indirectly disturbs the composition of gut microbiota, which in turn affects the degree of hippocampal neurogenesis in the brain of mice. There is a bidirectional interaction between gut microbiota and brain.