Regeneration of respiratory epithelia in the rat after free grafting.

Following free grafting of septal mucosa from the rat to the rectus abdominis muscle, the mucosal membrane was found to degenerate into a flat squamous epithelium with loss of the majority of differentiated epithelial cells. Both the goblet cells and ciliated cells regenerated from stem cells, which appear in large numbers 2 days after transplantation. Microvilli were found initially on the surfaces of developing ciliated cells and were replaced 21 days post-grafting by cilia. The number of goblet cells during regeneration at first exceeded that of the ciliated cells, but decreased with the passage of time. After 4 months there were more ciliated cells, with the respiratory epithelium now appearing no different than the initially transplanted nasal mucosa.