Novel Probiotic Lactic Acid Bacteria Were Identified from Healthy Infant Feces and Exhibited Anti-Inflammatory Capacities

The current study aims to evaluate the probiotic potential of lactic acid bacteria isolated from infant feces, and select candidates to be used as potential antioxidants for the treatment of oxidative stress-related diseases; To meet the criteria for probiotic attributes, the isolates were subjected to various in vitro tests and 16S rRNA genotypic characterization. Besides, anti-inflammatory and anti-oxidative effects of selected isolates were separately assessed by real-time quantitative PCR and Western blot; The selected strains belonged to Lactobacillus gasseri, Lactiplantibacillus plantarum and Lacticaseibacillus rhamnosus. Notably, three selected strains (L. gasseri FWJL-4, L. plantarum Fjias-5 and L. rhamnosus FSJ-13) particularly L. gasseri FWJL-4 significantly down-regulated mRNA expression levels of tumor necrosis factor α (TNFα), Interleukin-6 (IL-6) and IL-1β. Most importantly, three strains-treated RAW 264.7 murine macrophages displayed enhanced activities of antioxidant enzymes and reduced H2O2 production, which were associated with the enhanced expression levels of nuclear factor-erythroid 2 related factor 2 and heme oxygenase-1; Three selected strains, particularly L. gasseri FWJL-4, are good candidates that merit additional in vivo investigation for the validation and application of their health-promoting effects.