Fusion capability of rat embryonic oral tissue in vitro

Abstract

The premise that only an area limited to the medial edge of the palatal shelves has the potential to fuse was studied. Three series of 15 day, 16 hr embryo palates and tongues were cultured in vitro for 72 hr. In the first series the middle third of the face was cultured to study palatal shelf fusion. In the second the tongue was left in situ between the shelves and in the third littermate pairs of tongues were placed with their lateral borders in contact in the culture dishes. It was found that 16 of 20 palatal shelves fused, 39 of 40 palate to tongues fused, and fusion occurred between all the tongue pairs. In the first group the 4 shelves that failed to fuse were not in contact. Of group two, 32 areas of fusion revealed mesenchyme penetration and 7, lamination, there being mesenchymal penetration of all the tongue pairs. It is therefore concluded that fusion is not limited to a specific area of the palatal shelves but is a general property of oral tissues of embryonic rats of this age. Further it was found that for fusion to occur these tissues must be in close and quiescent contact.