It is proposed that both alteration of gut microbiota and their endotoxemia could be involved in the development of NAFLD and probiotics can delay the development of NAFLD by restoring the gut microflora, improve the expression of tight junction proteins (occludin), which can inhibit endotoxin circulation in blood by the LPS/TLR4 signaling 139. Here, TLR4 is linked to metabolic dysfunction-associated steatotic liver disease.