Rapid epithelial restitution of the rat gastric mucosa after ethanol injury.

The superficial gastric epithelia of anesthetized rats were exposed to absolute ethanol for 30 to 45 seconds and fixed at intervals of 0, 3, 7, 15, 30, and 60 minutes thereafter. The repair or restitution process was evaluated by quantitative light microscopy and by transmission and scanning electron microscopy. The brief exposure to absolute ethanol destroyed more than 95% of the superficial epithelial cells without producing deeper, macroscopic, hemorrhagic lesions. Three minutes after ethanol treatment more than 90% of the superficial necrotic epithelial cells had broken loose from the mucosa and exposed the basal lamina. Within 7 minutes about 45% of the exposed basal lamina was recovered by migrating squamous-low cuboidal epithelial cells from the gastric pits. After 15 minutes about 85% of the damaged surface was already covered with mucous cells, and at 1 hour about 95% of the previously denuded basal lamina was recovered with more normal appearing columnar epithelial cells. Migrating mucous cells from the gastric pits extended large lamellipodia over the denuded basal lamina and moved at approximately 1 to 2 micron/minute. Exposure of the healing surface to 10(-4) M cytochalasin-D inhibited lamellipodial formation and impeded cell migration. In addition, this drug produced large lucent vacuoles in the persisting mucous cells. These results suggest that destruction of the normal superficial gastric mucosa of the rat may not be as detrimental as generally assumed since the repair process is extremely rapid and efficient.