Abstract Interest in the utilization of novel plant-based extracts for supporting gut health and nutrition in companion animals is growing. The effect of betaine on canine intestinal barrier integrity and immune-related gene and protein expression by epithelial and macrophage-like cells was evaluated under conditions of inflammatory challenge from lipopolysaccharide (LPS) We evaluated: 1) the effect of betaine pre-treatment (0 to 1,000 µg/mL for 24 h) on the viability of canine intestinal epithelial MCA-B1 and macrophage-like DH82 cells; 2) epithelial barrier function of LPS-challenged MCA-B1 cells pre-treated with betaine, by measurement of 4-kDa fluorescein isothiocyanate (FITC-dextran (FD4) flux); 3) gene and protein expression of tight junction proteins and adhesion molecules using quantitative reverse transcription polymerase chain reaction (qRT-PCR) and proteomics; 4) anti and pro-inflammatory and regulatory gene expression in LPS-challenged, betaine pre-treated, MCA-B1, DH82 and peripheral blood mononuclear cells (PBMCs) and; 5) the phagocytic activity of DH82 cells pre-treated with betaine. No cytotoxicity of betaine against MCA-B1 or DH82 cells were observed. Betaine pre-treatment of MCA-B1 reduced FD4 permeability compared with untreated cells (P 0.05), accompanied by increased (mRNA) expression of claudin-1 (P 0.001) and E-cadherin (P 0.05) and increased protein expression of junctional adhesion molecules (P 0.05), vinculin (P 0.05) and aquaporin-3 (AQP3; P 0.01). Betaine pre-treatment of LPS-challenged cells also increased the expression of regulatory cytokines TGF-β1 (P 0.01), TGF-β2 (P 0.01), and IL-33 (P 0.05) in MCA-B1 cells and reduced the expression of IL-6 (P 0.05) and MyD88 (P 0.01) in DH82 cells compared with untreated cells. Additionally, betaine enhanced the phagocytic activity of DH82 cells (P 0.01) compared with untreated cells. Confirmatory studies in vivo are needed but these results suggest that plant-derived betaine has potential as a nutritional supplement for companion animals to support gut health and immunity.
Rekima et al. (2026) studied this question.