Anti-inflammatory effect of Bifidobacterium animalis subsp. lactis A6 on DSS-induced colitis in mice

Aims: This study aimed to investigate the protective effect of Bifidobacterium animalis subsp. lactis A6 on dextran sodium sulphate (DSS)-induced colitis in C57BL/6J mice. Methods and Results: Mice were randomly divided into three groups (n = 8 per group). Each group was administered with PBS (Control and DSS group) or B. lactis A6 with a dosage of similar to 4.0 x 10(9) CFU day(-1) (DSS + A6 group) for 21 consecutive days. The DSS and DSS + A6 group mice were ad libitum drinking 2.5% DSS water during day 15-21, while the Control group mice were given normal water. The administration of B. lactis A6 significantly inhibited DSS-induced bodyweight loss and colon shortening (p < 0.001), but showed no significant influence on the spleen enlargement (p > 0.05). The intestinal barrier integrity was improved by reducing colonic damage, recovering mucus layer loss and enhancing tight junction expression including ZO-1, occludin and claudin-1. In addition, B. lactis A6 attenuated the oxidative stress by decreasing MDA and increasing SOD and GSH levels in colon tissues. Moreover, B. lactis A6 suppressed DSS-induced inflammatory responses via downregulating TNF-alpha, IL-1 beta and IL-6 levels and upregulating IL-10 level in colon tissues. Conclusion: B. lactis A6 effectively alleviated DSS-induced colitis by maintaining intestinal barrier integrity, reducing oxidative stress and inhibiting inflammatory responses. Significance and Impact of the Study: This study suggests that B. lactis A6 could act as a candidate probiotic for UC treatment.

Automated summary

This study demonstrates that Bifidobacterium animalis subsp. lactis A6 has a protective effect against DSS-induced colitis by maintaining intestinal barrier integrity, reducing oxidative stress, and inhibiting inflammatory responses.