Alleviation of Helicobacter pylori- or aspirin-induced gastritis and neuroinflammation in mice by Lactococcus lactis and Bifidobacterium longum.

Helicobacter pylori (HP) causes gastritis and peptic ulcer. Therefore, we examined whether probiotics Lactococcus lactis P135 and Bifidobacterium longum P142, which inhibited HP growth by 37.9% and 35.3%, respectively, and HP-induced IL-8 expression in KATO III cells by 68.6% and 63.1%, respectively, compared to those of normal controls, could mitigate HP-induced gastritis and psychiatric disorder in mice. Oral administration of P135 and/or P142 alleviated HP- or aspirin-induced gastritis, colitis, neuroinflammation, and depression/cognitive impairment-like behavior. They also suppressed HP infection, neutrophil infiltration, and NF-κB activation in the stomach and TNF-α expression and NF-κB activation in the colon and hippocampus. of P135 and/or P142 alleviated HP- or aspirin-induced gut dysbiosis: they decreased Lachnospiracease, Helicobacteriaceae, and Akkermansiaceae populations and increased Bacteroidaceae and Muribaculaceae populations. These findings suggest that HP growth/inflammation-inhibitory P135 and/or P142 may alleviate gut inflammation (gastritis and colitis) and neuroinflammation through the suppression of neutrophil infiltration, NF-κB activation, and HP growth, thereby leading to the attenuation of systemic inflammation and psychiatric disorder.