Deletion of regulatory T cells supports the development of intestinal ischemia-reperfusion injuries

Background: Ischemia-reperfusion injury (IRI) of the intestine is associated with high morbidity and mortality in surgical and trauma patients. T cells participate in the pathogenesis of intestinal IRI, and T-cell depletion has been shown to inhibit inflammatory responses and diminish intestinal damage. However, the mechanism by which T cells contribute to intestinal IRI is not completely understood. Regulatory T cells (Tregs) are a specific subset of T cells that suppress immune responses and protect against tissue injuries. We hypothesized that Tregs might be involved in intestinal IRI. Materials and methods: We subjected C57/Bl6 mice to 30 min of ischemia by clamping the superior mesenteric artery followed by reperfusion. Animals were pretreated with the anti-CD25 monoclonal antibody or adoptive transfer of Tregs before induction of IRI. The number of inflammatory cells, the level of inflammatory factors, and intestinal permeability were assessed. Results: Partial depletion of Tregs with an anti-CD25 monoclonal antibody potentiated intestinal permeability induced by IRI. The Treg-depleted mice showed more neutrophils and CD4⁺ T cells. In addition, depletion of Tregs led to enhanced secretion of tumor necrosis factor-α, interferon-gamma, and interleukin (IL)-4 and reduced levels of IL-10. Furthermore, we performed adoptive transfer of Tregs and found that transfer of Tregs significantly inhibited the ischemia-reperfusion-induced increase in intestinal permeability. Conclusions: Our study indicated that Tregs participate in intestinal inflammatory responses induced by IRI and that targeting Tregs could be a novel therapeutic approach to intestinal IRI.