Avaliação dos efeitos probioticos e posbióticos das linhagens escherichia coli CEC15 e nissle 1917 em modelo murino de mucosite induzida por 5-fluorouracil

Abstract

Probiotics are live microorganisms that promote health benefits to the host. On the other hand, postbiotics are preparations of inactivated, lysed microorganisms, or their cellular structure maintained, containing or not their secreted metabolic products, and that promote benefits to the host when administered in appropriate quantities. Among probiotics, strains of Gram-negative bacteria of the Escherichia coli species stand out, such as the E. coli Nissle 1917 (EcN) strains that make up the Mutaflor probiotic, E. coli A0 34/86 present in Colinfant newborn, and the strains E. coli G1/2, G3/10, G4/9, G5, G6/7, and G8 that compose the Symbioflor2 probiotic. Both are marketed as supplements for improving intestinal health. Studies with the E. coli CEC15 strain have demonstrated its beneficial effects in TNBS-induced colitis models. This strain was isolated from the feces of suckling rats and demonstrated the ability to colonize the gastrointestinal tract of germ-free rats, triggering an adaptive response in the colonic epithelium, promoting remodeling of the epithelial tissue, and causing improvement in aspects associated with the intestinal barrier. Observing these results, the present work aims to evaluate the postbiotic effects in the form of heat-inactivated bacteria and cell-free supernatant, compared to the probiotic effect of EcN and CEC15 in attenuating 5-fluorouracil (5-FU)-induced intestinal mucositis in mice. Treatments with live and heat-inactivated CEC15 attenuated weight loss, preserved intestinal length, reduced histological damage, decreased loss of goblet cells, reduced neutrophil infiltration, and modulated the expression of inflammatory and barrier genes compared to 5-FU controls. EcN showed more limited effects. CEC15 increased the expression of mucin gene (MUC2) and tight junction protein TJP1. In general, CEC15 demonstrated protective effects against 5-FU-induced mucositis when administered as live, heat-inactivated, or as a supernatant. This suggests that CEC15 provides benefits through secreted metabolites and does not require viability. This study suggests that the anti-inflammatory and barrier-protective effects observed in the context of intestinal mucositis are associated with the action of CEC15.