Phenotypic screening of novel probiotics with potential anti-neuroinflammation activity based on cell and zebrafish models

Neuroinflammation, a major pathological factor contributing to various neurodegenerative diseases, is closely associated with gut microbiota imbalance. The aim of this study was to establish a rapid and efficient screening method to obtain potential anti-neuroinflammatory strains. Firstly, 94 strains isolated from different sources were screened against neuroinflammation in lipopolysaccharide (LPS)-activated BV-2 cells model to identify potential strains quickly. In vitro cellular experiments revealed that 21 strains significantly inhibited nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) activity, which were selected for further evaluation of gastrointestinal tolerance and adhesion properties. Among them, 18 strains with promising probiotic properties were further confirmed for anti-neuroinflammatory effects in vivo using the CuSO4-induced zebrafish model. The results showed that eight strains significantly mitigated the migratory behavior of zebrafish neutrophils and the mRNA expression level of pro-inflammatory cytokines IL-1β compared to other strains. Additionally, Lactiplantibacillus plantarum and Limosilactobacillus fermentum were identified as the main species by sequencing their 16S rDNA. In conclusion, this cell-zebrafish model is promising for high-throughput screening of novel probiotics with potential anti-neuroinflammation activity.