Effects of different environmental intervention durations on the intestinal mucosal barrier and the brain-gut axis in rats with colorectal cancer

Abstract An enriched environment (EE) is a promising strategy for protecting the intestinal mucosal barrier and regulating the brain-gut axis, but the optimal EE intervention duration is unknown. Here, different EE intervention durations were applied to assess the optimal intervention duration in rats with colorectal cancer. We used a rat model of 1, 2-dimethylhydrazine-induced colorectal cancer. The rats were housed in an EE for 0, 2, 4, 8 weeks and 8-week blank group. The intestinal mucosa and serum TNF-α, IL-6, IL-10, ATP, CRF, and occludin levels and bacterial translocation (BT) were measured, and the intestinal mucosa morphology was evaluated. In 8 weeks, the effect of tumor on intestinal mucosal barrier was not obvious and the EE had a greater impact on it. Eight weeks of EE was more beneficial to the intestinal mucosal mechanical barrier than 2 or 4 weeks of intervention. A significant difference in BT was found between the 4- and 8-week groups. Overall, the analysis of inflammatory factor regulation revealed that the two blank groups exhibited the worst effect, and the intervention effect at 8 weeks was better than that at 2 and 4 weeks. CRF at 4 weeks was higher than that at 8-week blank group. The effect of 8-week intervention duration on the intestinal mucosal barrier was generally better than that of 2- and 4-week durations and intervention within 4 weeks can help to stabilize and promote the secretion of brain gut peptide, but the effect of different intervention durations on the brain-gut peptide levels was not obvious. In the future, we can further explore the molecular biological mechanism of the effect of different EE intervention durations on the intestinal mucosal barrier and analyze the effect of an EE on other brain-gut peptides.