Experimental study on embryogenesis of congenital diaphragmatic hernia.

The purpose of this study was to determine whether hypoplasia of the lung bud might be responsible for cases of congenital diaphragmatic hernia (CDH). The lung bud normally develops in close association with the posthepatic mesenchymal plate ( PHMP ). The PHMP appears dorsal to the liver or on the ventral aspect of the pleuroperitoneal canal when the lung bud enters the pleuroperitoneal canal. Later, the PHMP grows to join the costal mesenchymal tissue via the pleuroperitoneal fold, thereby forming the primitive diaphragm. The present study found that the PHMP plays a cardinal role in the development of the diaphragm and that hypoplasia of the lung bud preceded hypoplasia of the PHMP in mice with CDH produced by the administration of Nitrofen to their pregnant mothers. This, along with findings related to the development of the phrenic nerve, makes it possible that pulmonary hypoplasia is a causal factor in the origin of congenital diaphragmatic hernia.