Paraprobiótico baseado em Enterococcus faecalis protege da mucosite intestinal induzida por irinotecano em camundongos

Abstract

Irinotecan have as a side effect intestinal mucositis (IM), which is known to alter the intestinal microbiota, and despite the many studies conducted to elucidate the mechanisms by which it develops, it still has no preventive treatment. Paraprobiotics are compounds made of inactivated bacteria that have the ability to balance the gut microbiota, modulate the immune response and maintain the integrity of the intercellular junction zone, being an interesting and safe alternative for the prevention of IM. Objective. This study aimed to test the protective effect of paraprobiotic Enterococcus faecalis (EC-12) on irinotecan-induced intestinal mucositis. Material and Methods. C57BL/6 male mice received saline, irinotecan (75 mg/kg, i.p), EC-12 (0.3, 1 or 3 x 107 CFU/kg, p.o.) + irinotecan or Med Lan-S (paraprobiotic-based formulation, 3 x 107 CFU/kg, p.o.) + irinotecan. Body mass variation was assessed daily, and blood samples were collected for bacteremia evaluation. After euthanasia, the ileum was harvested for myeloperoxidase assay, histopathology, quantitative PCR, and immunofluorescence for macrophages (F4/80) and TLR4 expression. Results. The optimal therapeutic strategy was verified when EC-12, administered at 3 x 107 CFU/kg, started one week before the first irinotecan injection. EC-12 and Med Lan-S did not prevent the irinotecan-induced body mass loss. Conversely, EC-12 and Med Lan-S attenuated the irinotecan-induced neutrophil infiltration in the intestine and increased the villus/crypt ratio (P <0.05). Additionally, EC-12 and Med Lan-S reduced the mRNA expression of Cldn-2, Ocln, and Tlr4 versus the irinotecan group (P <0.05). Remarkably, irinotecan augmented the expression of Il-18, but only EC-12 was able to reduce its expression. The pre-treatment with EC-12, but not Med Lan-S, reduced the immunofluorescence of F4/80 and Tlr4 to similar levels as the saline group. Furthermore, EC-12 and Med Lan-S inhibited the bacterial translocation to the blood. Conclusion. Paraprobiotic EC-12 prevents the development of intestinal mucositis by downregulating the inflammatory response. Despite the protection provided by the paraprobiotic formulation (Med Lan-S), its complexity accounts for an innate immune-driven protective mechanism.