Intestinal
mucositis (IM) is a critical side-effect associated with
antineoplastic therapy. Treatment available is only palliative and often not effective. However, alternative therapeutic strategies, such as probiotics, have attracted significant attention due to their immune-modulatory action in several diseases. Thus, the present study aims to elucidate the therapeutic potential of the probiotic strain Bifidobacterium longum 51A in a murine model of
mucositis induced by
irinotecan. Due to the scarcity of studies on dose-response and viability (probiotic vs paraprobiotic), we first evaluated which dose and cell viability would be most effective in treating
mucositis. In this study, the oral pretreatment with viable B.
longum 51A at a concentration of 1 × 109 CFU/mL reduced the daily disease activity index (p < 0.01), protected the intestinal architecture, preserved the length of the intestine (p < 0.05), and reduced intestinal permeability (p < 0.01),
inflammation, and oxidative damage (p < 0.01) induced by
irinotecan. Also, treatment with B.
longum 51A increased the production of
secretory immunoglobulin A (p < 0.05) in the intestinal fluid of mice with
mucositis. Furthermore, B.
longum 51A reversed the
mucositis-induced increase in Enterobacteriaceae bacterial group in the gut (p < 0.01). In conclusion, these results showed that
oral administration of B.
longum 51A protects mice against intestinal damage caused by
irinotecan, suggesting its use as a potential probiotic in
therapy during
mucositis.