动物造模 z-bio 2021-09-27 270

　　Objective: To discuss in vitro whether the supernatant of Lactobacillus rhamnosus (LGG-CM) can block the bacterial meningitis caused by E. coli K1 strain by inhibiting the NF-κB pathway.

　　Methods: Human brain microvascular endothelial cells (HBMEC) were used to construct an in vitro blood-brain barrier model; immunoblotting was used to study whether LGG-CM could inhibit E. coli K1 from activating the NF-κB pathway; after invasion experiments and neutrophil migration experiments, LGG was studied -Can CM inhibit bacterial invasion and neutrophil migration; the expression of adhesion molecule CD44 and tight adaptor protein ZO-1 was studied by immunoblotting; the intracellular distribution of ZO-1 protein was detected by immunofluorescence; blood brain outside the plane of Transwell tree In the barrier model, the effect of LGG-CM on maintaining the integrity of the cell barrier was evaluated through the TEER value and bacterial migration experiments.

　　Result: The result of western blot indicated that LGG-CM can inhibit E. coli K1 from activating the NF-κB pathway, thereby inhibiting the invasion of E. coli K1 and the migration of neutrophils. At the same time, LGG-CM can inhibit E. coli K1 from up-regulating the CD44 protein and down-regulating the tight adaptor protein ZO-1. In addition, LGG-CM can significantly slow down the decrease of TEER value and prevent E. coli K1 from crossing the external blood-brain barrier.

　　Conclusion: In vitro experiments indicate that LGG-CM can prevent bacterial encephalitis caused by E. coli K1 by inhibiting the activation of NF-κB pathway, blocking E. coli K1 invasion and neutrophil migration, and maintaining the integrity of the blood-brain barrier.