OBJECTIVETo study the expression of Wnt5a protein in the terminal rectum of children with anorectal malformation (ARM) and the possible association between Wnt5a and ARM.

METHODSSpecimens were obtained from 20 children with ARM, 7 children with acquired rectovestibular fistula and 6 children with non-gastrointestinal tract disease (control group). The expression of Wnt5a protein in the terminal rectum was determined by immunohistochemistry and Western blot.

RESULTSWnt5a was mainly expressed in the rectum of the myenteric nerve plexus, mucosal layer and submucosa in the control group. Compared with the control group, Wnt5a expression in the terminal rectum decreased significantly in the ARM group, and decreased more significantly in children with high ARM. The results of Western blot showed the expression of Wnt5a protein in the high, intermediate and low ARM groups were significantly lower than that in the acquired rectovestibular fistula and the control groups (P<0.01). The expression of Wnt5a protein in the high and the intermediate ARM groups were also lower than that in the low ARM group (P<0.01). There was no significant difference in the Wnt5a protein expression between the acquired rectovestibular fistula and the control groups.

CONCLUSIONSThe expression of Wnt5a in the termina1 rectum decreases in children with ARM, suggesting Wnt5a may play an important role in the development of ARM.