Degeneration and regeneration of the lip mucosal epithelium after cryo treatment in mice

The process of degeneration and regeneration of the lip mucosal epithelium after cryo treatment was observed by transmission electron microscopy. The epithelial cells were degenerated by the formation of ice crystals and subs equently detached from the basement membrane, forming a blister cavity, The separation occurred be tween the epithelial cells and the lamina densa, le aving a small amount of cell debris on the lamina densa, The surviving cell s at the periphery of the blister cavity, especially the cells in the basal half of the epithelium, provided the regeneration cells. They migrated ove r the cell debris, attached to the lamina densa and gradually phagocytozed it. Finally, they formed hemidesmosomes with the old lamina densa, The conn ections between the epithelial cells by desmosomes were so tight that desmo somes were preserved even between dead cells and between dead and living ce lls. Regenerating cells were moving in a multilayered form, remaining conne cted to each other by the dosmosomes. They were seen to divide by mitosis a nd thereby increase the number of the cell layer, whilst maintaining their connections with the neighbouring cells. Copyright((C) 2001 S.KargerAG, Bas el.