LAUSR

Objectives The beneficial role probiotics in lowering colonic inflammation has been demonstrated previously. However, most probiotics are very susceptible to the harsh conditions during GI transit, which significantly affect their functions in the body. Here, we encapsulated the Lactobacillus salivarius Li01 (Li01) in a layer-by-layer MgO doped delivery system (LbL). Methods Li01 LbL was prepared using alginate, chitosan and MgO, and lyophilized by freeze-drying. The encapsulated Li01 was determined in vitro under simulated GI conditions. The ameliorative effect of the prepared Li01 LbL on the dextran sulfate sodium (DSS)-induced colitis in mice was investigated by oral gavage. Meanwhile, gut microbial variation were also detected through 16 S rRNA genes by Miseq sequencing in order to determine the correlations among probiotics, colitis and gut microbiota. Results Our results demonstrated that the Li01 LbL developed in this study improved the viability of Li01 in the GI tract as well as facilitate mucosadhesion on the intestinal surfaces, compared to non-encapsulated Li01. Notably, oral administrations of Li01 LbL reduced DSS-induced mucosal inflammation, as defined by colonic histology and expression of pro-inflammatory markers such as IL-6, TNF-α and IL-10. However, no significant difference was found between the model mice fed with free Li01 and saline buffer, which may be due to low viability of the probiotics. The 16 S rRNA sequencing results also showed an obvious increase of the bacterial abundance in the model fed with Li01 LbL, suggesting a mechanism dependent on the modulation of gut microbiota. Conclusions The encapsulation approach plays a critical role for improving efficacy of probiotics in prevention or treatment of gut microbiota-related disease. Funding Sources National Key Science and Technology Project of China (2018YFC2000500).