Dose-Dependent Anti-Inflammatory Effects of Live and Heat-Treated Ligilactobacillus salivarius and Bifidobacterium breve via NF-κB and COX-2 Modulation in an In Vitro Model of Airway Inflammation.

BACKGROUND: Probiotics are live microorganisms known for their health-promoting effects, particularly in modulating immune responses and reducing inflammation within the gastrointestinal tract. Emerging evidence suggests probiotics may also influence respiratory health, prompting investigation into their potential therapeutic application in lung inflammation. METHODS: This study examined the anti-inflammatory effects of Ligilactobacillus salivarius (LS01 DSM 22775) and Bifidobacterium breve (B632 DSM 24706) on inflamed pulmonary epithelial cells. Lung carcinoma epithelial cells (A549) and normal bronchial epithelial cells (16HBE) were stimulated with IL-1β and treated with viable and heat-treated probiotics. RESULTS: CCL-2 levels were significantly reduced by up to 40%, in A549 by viable form (10(5)-10(7) AFU/g), instead of in 16HBE by heat-treated form (10(7)-10(9) TFU/g). In A549 cells, TNF-α decreased by 20-80% with all formulations; instead, in 16HBE cells, IL-8 was reduced by viable strains (10(7) AFU/g) by approximately 50%, while heat-treated strains (10(9) TFU/g) decreased both IL-6 and IL-8 by 50%. All effective treatments completely inhibited IL-4 and eotaxin and suppressed NF-κB activation in both cell lines, with up to 80% reduction in phospho-p65 levels. In A549 cells, heat-treated strains fully blocked PGE2 production; instead, all four probiotics significantly inhibited COX-2 expression by approximately 50%. CONCLUSIONS: These findings demonstrate that both viable and heat-treated probiotics can modulate inflammatory responses in pulmonary epithelial cells, suggesting their potential application in inflammatory respiratory diseases. Heat-treated formulations may be particularly suited for local administration via inhalation, offering a promising strategy for targeting airway inflammation directly.