Neutrophil infiltration in the segments proximal to the site of obstruction
Myeloperoxidase (MPO) staining was performed to assess neutrophil infiltration. The neutrophil count in the different segments ofCftr+/+ and Cftr-/- intestine were very low, but there was a significant increase in the ileum and mid-distal colon between Cftr+/+ andCftr-/- mice, independent of treatment. Neutrophil infiltration was strongly increased in the segments immediately proximal to the site of obstructions, but not in the mid-distal colon, which was the segment that was always distal to the obstruction (Figure 7a,b). To verify this finding, we measured the mRNA expression of Ly6g, a marker for differentiated neutrophils and granulocytes (Figure 7c). Ly6g expression was much higher in the segments proximal to the obstruction.