Exploring the alteration of gut microbiota in the rats with steroid-induce osteonecrosis of the femoral head.

BACKGROUND: Osteonecrosis of the femoral head usually occurred after glucocorticoid (GC) therapy. The gut microbiota was considered an indispensable part of maintaining human health, and the concept of the gut microbiota -bone axis was also proposed. In our study, we aimed to elucidate the link between steroid-induce osteonecrosis of the femoral head (SIONFH) and the gut microbiota; Methods: The methylprednisolone (MPS) was used to establish the rat model with SIONFH. During rat modeling, some plasma indexes and the gut microbiota were detected by ELISA and 16 S rRNA gene sequencing. In addition, we deeply explore the relationship between these plasma indexes and gut microbiota by using various bioinformatic methods; Results: Our data revealed that there were specific microbes colonized in the gut of rat with SIONFH. Compared to the control group, Prevotellaceae and Oscillospiraceae were replaced by Lactobacillaceae and Bacteroidaceae families in the SIONFH group. Equally, we found that the decreased beneficial gut microbiota maybe a mediation effect between the SIONFH and the increased IgM level; Conclusions: Oscillospiraceae and Prevotellaceae had bone-protective effects and balance the osteoblast-osteoclast balance. Our study showed that the loss of Oscillospiraceae and Prevotellaceae was associated with SIONFH, an effect mediated by elevated plasma IgM.