Screening of Lactobacillus plantarum LPH10 and Its Anti-inflammatory Properties: Acid and Bile Salt Tolerance, Bacteriostatic Activity and Regulation of NF-κB/IRF Pathways.

Inflammatory diseases pose a significant threat to human health, and probiotics have increasingly drawn substantial attention for their anti-inflammatory potential. In this research, a model of inflammation was constructed using J774-Dual reporter cells. Lactobacillus plantarum LPH10 with anti-inflammatory properties was screened from Yangzhou pickles. Its characteristics of acid tolerance, bile salt tolerance, bacteriostatic ability, and inhibition of the Salmonella-induced inflammation were evaluated. The results demonstrated that LPH10 exhibited excellent tolerance in simulated gastric acid (pH 3.0) and small intestinal bile salt (0.3%) environments, maintaining high survival rates at both 2 h and 4 h, indicating remarkable acid and bile salt resistance. Bacteriostatic assays demonstrated that LPH10 was effective in restraining the growth of Salmonella enteritidis and Escherichia coli. Moreover, LPH10 displayed sensitivity to a broad spectrum of antibiotics and did not notably affect the viability of RAW264.7 macrophages, which indicated its safety. LPH10 was discovered to be able to potently suppress the activation of the NF-κB and IRF signaling pathways triggered by LPS and S. enteritidis. In the LPS-induced inflammation model, LPH10 downregulated the expression of proinflammatory cytokines such as IL-1β, IL-6, and TNF-α, while upregulating the expression of the anti-inflammatory cytokine IL-10. In the Salmonella-induced inflammation model, LPH10 also regulated the expression levels of inflammatory cytokines, thereby exerting potent anti-inflammatory effects. Overall, L. plantarum LPH10 was successfully screened due to its multiple beneficial properties. This study provides a solid theoretical basis and experimental support for the screening and application of functional anti-inflammatory probiotics and will provide new approaches and probiotic candidates for the development of anti-inflammatory foods and the treatment of inflammatory diseases.