Effect of TrkB-PLC/IP3 pathway on intestinal inflammatory factors and enterocyte apoptosis in mice with colitis

In this study, we aimed to explore the effect of TrkB-PLC/IP3 pathway on intestinal inflammatory factors and enterocyte apoptosis in mice with colitis. The mouse model of ulcerative colitis was established by medication, and 40 SPF C57BL/6J mice (8 weeks old) were randomly divided into normal group (healthy mice, n = 10), control group (sham-operated mice, n = 10), model group (model mice without any treatment, n = 10), and K252a group (model mice treated with 100 μmol/kg TrkB-PLC/IP3 pathway inhibitor for 5 days before clysis, n = 10). The results showed that mice in the model and K252a groups, as compared with normal and control groups, had no significant changes in the levels and protein expressions of serum tumor necrosis factor-α (TNF-α) and TNF-γ in the colon tissues (P>0.05), and had a significant increase in disease activity index, colon mucosa damage index, tissue damage index scores, and levels and protein expressions of serum interleukin-4 (IL-4) and IL-8, but had a significant decrease in the level and protein expression of serum IL-10 (P<0.05). Mice in the model and K252a groups showed blocked enterocyte cycle progression, elevated apoptosis ratio, and significantly increased mRNA and protein expressions of Caspase3, Bax, FasL, and Fas, but significantly reduced mRNA and protein expressions of p-TrkB, PLC-γ1, IP3, and Bcl-2 (P<0.05). Moreover, intestinal inflammation and apoptosis induced by colitis in the K252a group became more aggravated by inhibiting the activity of TrkB-PLC/IP3 pathway. In conclusion, inhibition of TrkB-PLC/IP3 pathway can increase the expression of intestinal inflammatory factors and promote enterocyte apoptosis in mice with colitis.