Postbiotic Administration Ameliorates Colitis and Inflammation in Rats Possibly through Gut Microbiota Modulation

Postbiotics
are preparations of inanimate microorganisms and/or
their components that are beneficial to host health. Compared with
probiotics, the postbiotic dose required for exerting obvious protective
effects is unknown. Thus, we conducted a dose-dependent postbiotic
intervention study in dextran sulfate sodium (DSS)-induced colitis
rats. The trial included five rat groups, including: control without
DSS/postbiotic treatment, group C; 7-day DSS treatment, group D; 14-day
low, medium, and high probiotic doses (0.1, 0.2, 0.4 g/kg; groups
L, M, H, respectively) after DSS induction. We found that postbiotic
intervention effectively mitigated the symptoms and inflammation in
colitis rats, evidenced by the improved spleen index, less severe
colon tissue damage, and changes in serum cytokine levels (decreases
in tumor necrosis factor-α and interleukin-1β; increase
in interleukin-10) in postbiotic groups compared with group D. Moreover,
the therapeutic effect was dose-dependent. Fecal metabolomics analysis
revealed that the postbiotic recipients had more anti-inflammatory
metabolites, namely, salicyloyl phytophingosine, podophylloxin, securinine,
baicalein, and diosmetin. Fecal metagenomics analysis revealed that
the postbiotic recipients had more beneficial microbes and less pro-inflammatory
bacteria. This study confirmed that postbiotics are effective in alleviating
colitis in a dose-dependent manner. Our findings are of interest to
food scientists, clinicians, and the health food industry.