Bifidobacterium promotes RGCs survival by vague nerve mediated activation of Muller cells

Optic nerve injury is a dominant cause of irreversible blindness worldwide. Once the neurons and their axons are damaged, they cannot regenerate. Thus, it is critical to reduce neuronal damage and increase neurotrophic factor production to prevent blindness. We have discovered that the administration of Bifidobacterium protects retinal ganglion cells from death during optic nerve injury. Bifidobacterium induces changes in the flora composition, and especially, increases the abundance of Lactobacillus. This optimization of gut microbiota transmits protective signals to the retina through the vague nerve, which in turn triggers the ERK Fos signaling pathway in the retina, enhances the activity of Muller cells, and promotes the production of neurotrophic factors. These results provide evidence that Bifidobacterium promotes RGCs survival by vague nerve mediated activation of Muller cells.