ABSTRACT
In this present study, bioinformatics analysis and the experimental validation method were used to systematically explore the antioxidant activity and anti-inflammatory effect of Lactiplantibacillus plantarum A106, which was isolated from traditional Chinese pickles, on lipopolysaccharide (LPS)-induced RAW264.7 macrophages. L. plantarum A106 had a good scavenging ability for DPPH, ABTS, and hydroxyl radicals. Furthermore, L. plantarum A106 could increase the activity of RAW264.7 macrophages; raise the SOD and GSH levels, with or without LPS sensitization; or decrease the MDA, TNF-α, and IL-6 levels. In order to deeply seek the antioxidant and anti-inflammatory role and mechanism, bioinformatic analysis, including GO, KEGG, and GSEA analysis, was used to conduct an in-depth analysis, and the results showed that the LPS treatment of RAW264.7 macrophages significantly upregulated inflammatory-related genes and revealed an enrichment in the inflammatory signaling pathways. Additionally, a network analysis via the Cytoscape software (version 3.9.1) identified key central genes and found that LPS also disturbed apoptosis and mitochondrial function. Based on the above bioinformatics analysis, the effects of L. plantarum A106 on inflammation-related gene expression, mitochondrial function, apoptosis, etc., were detected. The results indicated that L. plantarum A106 restored the declined expression levels of crucial genes like TNF-α and IL-6; mitochondrial membrane potential; and apoptosis and the expression of apoptosis-related genes, Bcl-2, Caspase-3, and Bax. These results suggest that L. plantarum A106 exerts antioxidant activity and anti-inflammatory effects through regulating inflammatory and apoptosis-related gene expression, restoring the mitochondrial membrane potential.
ABSTRACT
Food allergy is an abnormal immune reaction triggered by food protein antigens. Relevant studies have suggested that probiotic supplementation was with the potential to alleviate food allergy. This study aimed to explore the effects of Lactobacillus plantarum A56 on the alleviation of ovalbumin (OVA)-induced food allergy via immunomodulatory function, antioxidation, and modification of intestinal microbiota. Balb/c mice were sensitized with OVA (20 µg/mouse) by intraperitoneal injection for 3 weeks and accompanied by oral administration of L. plantarum A56 (109 CFU/mL), subsequently with orally challenged twice by OVA at 50 mg/mL for 1 week. The results showed that oral supplementation of L. plantarum A56 could effectively relieve allergic symptoms of mice, and decreased OVA-specific IgE and IgG1 concentrations. It also declined interleukin (IL)-4 level, raised interferon-γ (IFN-γ) in serum, and splenocyte supernatant, and the qPCR results were consistent with above results. Moreover, L. plantarum A56 treatment also fortified superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) levels, and reduced malondialdehyde (MDA) level in serum. The increased nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and forkhead box O1 (Foxo1) expression indicated that L. plantarum A56 exerted antioxidation through Nrf2-Foxo1 pathway. In addition, L. plantarum A56 treatment elevated Bacteroidetes richness, ASV/OTU number, species diversity, etc. Notably, Spearman correlation analysis indicated that Bacteroidetes displayed obviously negative correlation with IgE and IgG1, but Actinobacteria and Acidobacteria exhibited significantly positive correlation with IgG1 and IgE. Collectively, these results suggested that L. plantarum A56 could alleviate OVA-induced food allergy by regulating Th1/Th2 imbalance, antioxidation, and modulating intestinal microbiota.