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 coiled, flexed, and regionalized structure. The changes in gut morphology coincide with the differentiation of multiple cell types in concentric layers, and include colonization by migratory neuron precursors, and the development of gastrointestinal motility. We describe a reliable method for growing embryonic mouse intestine in vitro by the attachment of segments of intestinal tract by their cut ends, with the intervening region suspended in the culture 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 to support neural precursor migration, and contractile activity were assessed. The increase in size of the cultured explants was not large, but morphogenesis proceeded, best exemplified by elongation of the caecum. Cell differentiation also proceeded. In the mucosa, goblet cells differentiated. Muscle layers, characterized by desmin expression, and kit-positive interstitial cells of Cajal differentiated in the correct positions. Where segments initially included neural precursors in a small sub-region, these migrated and proliferated to form uniform neuronal networks throughout the entire explant, and the cells expressed the neuron markers nitric oxide synthase and neuron 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 bend (unlike on solid support cultures), while retaining its rostrocaudal identity.