Immunolocalization Of The Gap Junction Protein Connexin43 In The Human Normal And Hirschsprung's Disease Bowel

Objective: Hirschsprung's disease (HD) is a common congenital gastrointestinaldisease characterized by aganglionic,dysformation of the intestinal nerve system.Numerous abnormalities of innervation of the bowel have been described in HD ,but the actual cause of dysmotility of the bowel in HD remains unclear.The gap junctions are regarded as the junctional part of the network between cells of bowel,and it plays an important role in communication. Although there have been several studies reporting distribution of GJ in the animal,there is little information on the crucial role of Gap junctions in the intercellular communication in the gut musculature.The aim of this study is to investigate the immunolocalization of the Gap junction protein connexin43 in the normal and Hirschsprung disease bowel to discuss the relationship between HD and connexin43.Method: The immunoreactivity of Gap junction protein connexin43 wasevaluated by immunohistochemical method using anti-connexin43 multi-antibody in 30 HD patients and 30 controls.The ultrastructure was observed by electrical microscope and the specimens were collected from bowel at pull-through operation on 4 HD patients.The control colon tissues were obtained from surgical resection performed for colonal carcinoma and intussusception patients.The previous bowel motility of these patients had been proved to be normal.Tissue was defined as normal when the section was not invaded by the tumor.Result: Moderate to strong immunostainning was observed at the circularmuscle,submucosal region in normal bowel and in ganglionic bowel from patients with HD.The immunoreactivity of connexin43 was either absent or weak in the longitudinal bowel of both normal bowel and HD bowel,and in the aganglionic part of HD bowel.Many gap junctions were observed between Interstitial cells of Cajal andsmooth muscle cells, between smooth muscle cells and smooth muscle cells in ganglionic part of HD bowel,which was absent or less in the aganglionic part.Conclusion: 1. The different distribution of connexin43 in the normal bowelmay be due to the generation and the propergation of the electrical current and the activing method of bowel muscles; 2.The lack expression of Connexin43 in the aganglionic bowel of HD suggest that the impaired intercellular communication between cells may partly be responsible for the motility dysfunction in HD.Postgraduate: Jicui Zheng (Pediatric Surgery) Directed by: Viceprofessor Chuanmin Yang...