| Background: Congenital megacolon is also called Hirschsprung's disease, HD. It's a common gastrointestinal abnormality in children. The morbidity is about 1/5000. The ratio of boy and girl is 4:1. The primary pathology of Hirschsprung's disease (HD) is a congenital absence of ganglion cells in the caudal most gut (rectal or rectosigmoid) and it was clear now, the pathologic of HD is the absence of ganglion cells that has been attributed to the failure of migration of neural crest cells. If the development of enteric nervous system is influenced by some factors at different development stage, it will result in various symptoms of HD. In HD patients, the distal colon is spastic segment (aganglionic), the proximal colon is normoganglionic segment. Between the two parts is transitional segment (hypoganglionic). The spastic aganglionic bowel is often innervated by a network of hypertrophied nerve fibres. The cause of the failure of migration of neural crest cells has not been clearly known by now. HD is regarded as the result interaction of inherited factor and environmental factor. With the rapid development of the molecular biologic technology, today, it is define that some genes have relationship with the cause of HD. Recently mutations of SOX10, SRY(Sex determing Region Y gene) related high mobility group-BoX gene 10,have been identified in patients with HD but only inthose with Waardenburg-Shah syndrome.Objective: The current study through the technology of reverse transcription-polymerase chain reaction,RT-PCR to investigate the expression of SOXlOmRNA in the sporadic HD patient's bowel, to understand the molecular basis for the pathogenesis of HD. Materials and Methods: we studied colon tissues which were obtained from 12 patients with HD during pull through operation. Age ranged from nine days to forteen years, including 3 newborns, 8 infants and 1 child . There were eight boys and four girls.The ration of boy and girl is 2:1. Seven patients had classical short segment aganglionosis with rectal or rectosigmoid involvement and one patient had aganglionosis extending to the splenic flexure and four patients had ordinary segment aganglionosis. There was no family history and no associated major anomalies or syndromes. After mobilisation of the hypertrophied and spastic colon, colon tissue samples were taken from the normal segment, transitional segment (hypoganglionic), and spastic segment (aganglionic). Tissues from normal controls were obtained from colon biopsies at gastrointestinal operation for age matched patients without HD (n=12). These infants and children had anorectal anomalies and necrotising enterocolitis of the distal gut and underwent colostomy or closure of colostomy at unaffected parts.of the colon. Fresh bowel speciments kept freezing in liquid nitrogen, or stored at -86°C after resection and the smooth muscle layer was denuded from the mucosa for RT-PCR ( reverse tianscription-polymerase chain reaction). The data of results were analyzed with the SPSSIO.O statistical software. Results: (1) We found that SOXlOmRNA was expressed in all bowel segments both in normal infants and HD patients. SOXlOmRNA expression (the mean of SOX10/β-actin ration) in the colon different segments in HD patients as fellows: spastic segment (or aganglionic), 1.0881 ±0.1356; transitional segment (hypoganglionic), 1.3189 ± 0.0569; normal segment, 1.3439±0.0446. (2) In 12 normal control samples (normal infants), 1.3416±0.0605. (3) Use paired-samples / test, compared separately with spastic segment and transitional segment(P<0.05), spastic segment and normal segment(P<0.05) in HD patients, spastic segment and normalinfants(P<0.05). All have the same significant difference. (4) It is interesting that there is no significant difference between transitional segment and normal segment(P >0.05) in HD patients, between transitional segment and normal infants(P>0.05), normal segment and normal infants(P>0.05). (5) By means of ANOV(Analysis of Variance), there is similar significant difference between spastic segment and transitional segment, spastic segment and normal segment in HD patients, spastic segment and normal infants. SOX10mRNA expression in 12 normal control samples was similar to that of the hypoganglionic and normal segments of patients. There is no significant difference among transitional segment, normal segment in HD patients and normal infants. Conclusion:(1) SOX10mRNA expression reduced gradually in normal segment, transitional segment, spastic segment in non-syndromic HD patients. But there is no significant difference between normal segment (non-syndromic HD) and normal infants, suggest that this abnormal distribution is associated with the development failure of the enteric nervous system.(2) SOX10mRNA expression lower in all spastic segment in non-syndromic HD patients indicated that the SOX10 gene expressed in the sacral region may be involved in the pathogenesis of the abnormal nerve trunks through interaction with other factors.(3) This study revealed the differ SOX10mRNA expression in different segments in non-syndromic HD patients and normal infants and concluded that SOX10 is normally required postnatally in the functional maintenance of the entire enteric nervous system, if the absence of ganglion cells expression reduced, it may be aroused the intestine spastic and stricture and made it's function obstacle. But, whether the low SOX10mRNA expressionresult to the absence of ganglion cells or not, there will have some moreinvestigate.
|
PDF Full Text Request