Methods to measure gastric mucosal lesions in the rat.

The maintenance of gastric mucosal integrity is ensured by a dynamic balance between protective and noxious factors. The gastric mucosa has multiple protective mechanisms that allow the mucosa to withstand frequent exposure to potentially damaging agents such as acid and peptic secretions, bacterial products, ingested food, alcoholic beverages, and certain drugs. The imbalance between defensive and aggressive factors is at the basis of the formation of erosions/lesions or ulcerations of the gastric mucosa. The difference between an erosion/lesion and ulceration is that the former is confined to the mucosa, while an ulceration penetrates to the muscularis mucosae. This unit presents two models of acute mucosal lesions induced in the rat by gastrotoxic agents acting through different mechanisms of action. The protocols explain how to measure gastric mucosal lesions by microscopic examination of the stomach by light microscopy and by scanning electron microscopy.