The novel insight into anti-inflammatory and anxiolytic effects of psychobiotics in diabetic rats: possible link between gut microbiota and brain regions.

Purpose: Type 2 diabetes mellitus (T2DM) was associated with gut microbial impairment (dysbiosis) and neurological and behavioral disorders. The role of the gut-brain axis in the management of many diseases including T2DM has been the focus of much research activity in the recent years. However, a wide knowledge gap exists about the gut microbial effects on the function of glia cells. Hence, the present study was aimed to examine the effects of psychobatics on dysbiosis and glia cells function in enteric and central nervous system with an inflammatory insight in T2DM.
Methods: Thirty rats were treated by Lactobacillus (L.) plantarum, inulin, or their combination (synbiotic) for 8 weeks after inducing T2DM. Fecal sample was collected to evaluate gut microbial composition. Then, the rats were sacrificed, and the colon, amygdala, and prefrontal cortex (PFC) were studied.
Results: T2DM resulted in dysbiosis and increased levels of glial cell-derived neurotrophic factor (GDNF), glial fibrillary acidic protein (GFAP), and inflammatory markers (IL-17, IL-6, and TLR-2) in the colon and brain. However, concurrent supplementation of L. plantarum and inulin could improve the gut microbial composition as well as reduce the levels of inflammatory cytokines. While the administration of L. plantarum led to a significant decrease in TLR-2 as well as GDNF and GFAP only in the amygdala, the synbiotic intake could make such changes in the colon, amygdala, and PFC.
Conclusions: Our findings demonstrated an innovative approach to the beneficial effects of psychobiotics in neuroinflammation and behavioral performance through gut microbiota changes, focusing on possible role of glial cells in gut-brain axis.