THE OBSERVATION OF THE DEVELOPMENT OF COLON ENS IN HUMAN EMBRYOS

Objective To offer reference for further studying the pathogeny of congenital megacolon by studying the development of colon ENS in human embryos. Methods Using protein gene product 9 5 and S\|100 protein as the first antibodies in PAP immunohistochemistry to show the neurons and neuroganglion in colon ENS. Results The development of colon ENS and colon wall has distinct stages.During early stage, from second to third month,the development of colon wall is poor.Then there appear thin layers of circular muscle and mucosa.Only few S\|100 protein immunoreative nerves can be observed in the place of primary myenteric plexus.At middle stage, from forth to fifth month, the colon wall has differentiated four layers with plentiful of villi.The neurons in myenteric plexus iscrease clearly,which scatter in whole myenteric plexuses and migrate into submucosa and mucosa gradually.The myenteric plexus is composed of primary and secondary strands displaying a complex nervous meshwork.As for later stage, from sixth to ninth month,the four layers thickened.In myenteric plexus,the immunoreactive perikara and nerves become different size ganglions by degrees.In the network,there appear the tertiary strands.The outer and inner submucosa plexuses have differentiated well. Conclusion The development ENS has distinct stages.During early stage of the development, the nerves begin to appear on wall.They develop and differentiate in middle stage.As for later stage, the nerves in the four layers has developed and matured.In different developmental stage, original causes of disease pathogenesis will result in various symptoms of cogenital megacolon.\;