Catenary cultures of embryonic gastrointestinal tract support organ morphogenesis, motility, neural crest cell migration, and cell differentiation

The embryonic gastrointestinal tract develops from a simple tube into a coi led, flexed, and regionalized structure. The changes in gut morphology coin cide with the differentiation of multiple cell types in concentric layers, and include colonization by migratory neuron precursors, and the developmen t of gastrointestinal motility. We describe a reliable method for growing e mbryonic mouse intestine in vitro by the attachment of segments of intestin al tract by their cut ends, with the intervening region suspended in the cu lture medium. These are termed "catenary cultures." E11-E11.5 mouse midgut, hindgut, or mid- plus hindgut segments were grown in catenary culture for up to 10 days and their growth, morphology, cell differentiation, ability t o support neural precursor migration, and contractile activity were assesse d. The increase in size of the cultured explants was not large, but morphog enesis proceeded, best exemplified by elongation of the caecum. Cell differ entiation also proceeded, In the mucosa, goblet cells differentiated, Muscl e layers, characterized by desmin expression, and kit-positive interstitial cells of Cajal differentiated in the correct positions. Where segments ini tially included neural precursors in a small sub-region, these migrated and proliferated to form uniform neuronal networks throughout the entire expla nt, and the cells expressed the neuron markers nitric oxide synthase and ne uron specific enolase. Gut motility was attained 5-6 days into the culture period, and both contractile- and mixing-type movements were observed. Thus , cell types representative of all three germ layer contributions developed , and in addition, the gut, being mainly free, was able to elongate and ben d (unlike on solid support cultures), while retaining its rostrocaudal iden tity, Dev Dyn 1999;214:239-247. (C) 1999 Wiley-Liss, Inc.