Effects of different doses lipopolysaccharides on the mucosal barrier in mouse intestine

Lipopolysaccharide (LPS), an important component in the outer membrane of the cell wall of Gram-negative bacteria, can induce a systemic inflammatory response and play an important role in bacterial infection and disease evolution. The thick layer of mucus covering the small intestinal villus acts primarily to the first barrier from damage by toxic substances. We aimed to study the effects of LPS on the intestinal mucus layer barrier. The results showed that the thickness of the mucus layer was significantly increased by a low dose of LPS. Further, LPS can cross this barrier into the blood, put the body in a state of chronic low-grade inflammation, and activate the body's immune response. However, after a long-term high dose of LPS exposure, a large number of lysosomes in goblet cells caused a loss of function, and mucus layer thickness was significantly decreased. A large amount of LPS stuck to the mucus, leading to normal LPS and inflammatory cytokines level of plasma. The intestinal tissue morphology was damaged, and many immune cells died through necrosis in the intestine. Collectively, the function of the goblet cell was normal, a low dose of LPS cannot be stuck to the mucus layer. However, a high dose of LPS stuck to the mucus when goblet cells caused a loss of function, which can be directly linked to the severity of the immunosuppression in the body.