[Regeneration of the thread-like papillae in the rat tongue]

The regeneration capacity of the filiform papillae of the rat tongue was studied after destruction through abrasion in 18 rats after time intervals of 1 1/2 days until 7 months. By abrasion were destroyed the epithelial layer, the tunica propria mucosae and part of the muscle layers. Lightmicroscopic investigation showed formation of new filiform papillae, similar in structure to the normal tissue. Scanning electron microscopic investigation brought further details. It showed clearly that in the regeneration area the newly formed filiform papillae were irregularly distributed and of different shapes. These studies make it clear that newly formed epithelial as well as connective tissue has a generally coded property to form new filiform papillae. No fungiform papillae were ever seen to regenerate. It is concluded that these are higher differentiated organs with no capacity to regenerate.