The rectosigmoid smooth muscle functions and distributions of neurotransmitters in fetal rats with anorectal malformations

Aim: Constipation, fecal insensitivity and fecal incontinence are frequently encountered problems in cases with anorectal malformation after surgical treatment. Despite improvement in surgical treatment, continuance of problems leads us to think that the dysfunctions of bowel and anal sphincter continue even structural disorder is treated in anorectal malformation. In our study, in experimental anorectal malformation rat model, contraction functions in rectosigmoid smooth muscle tissues and neuron specific enolase, substance P and vasoactive intestinale peptide densities have been investigated.Material and Method: The control group has been formed from fetal rats obtained by giving normal saline to Wistar Albino type pregnant rat on 11th day of pregnancy, the ethylenethiourea group has been formed by those whose anorectal malformation is not developed from fetuses obtained by giving ethylenethiourea and the ethylenethiourea-anorectal malformation group was constituted by those whose anorectal malformation is developed. Smooth muscle contraction and relaxation responses have been measured in the organ bath of rectosigmoid tissues of ten fetuses in each group. The immunohistochemical antibody staining results of the neuron specific enolase, substance P and vasoactive intestinale peptide at rectosigmoid smooth muscle tissues of 15 fetuses in each group have comparatively been analyzed among the groups.Results: Contraction responses have been received from the control and the ethylenethiourea groups with charbamylcholine application in the organ bath, whereas contraction response has not been received from the ethylenethiourea-anorectal malformation group. Neuron specific enolase and substance P densities have been found lower in the ethylenethiourea-anorectal malformation group when compared to the other groups, whereas vasoactive intestinale peptides densities have been found high in this group.Discussion and Conclusion: Absence of contraction response and high level of vasoactive intestinal peptide density at bowel smooth muscle in Ethylenethiourea-anorectal malformation group leads us to think that there are intrinsic nervous system disorders that appear as contraction non-response at rectosigmoid smooth muscle at anorectal malformations, and this is caused by high level of vasoactive intestinal peptide. In anorectal malformations, these findings appear to explain reasons of bowel and sphincter dysfunctions which occurrence following surgical treatment.Keywords: Anorectal malformation, Bowel smooth muscle, Neuron specific enolase, Substance P, Vasoactive intestinal peptide.