Autofluorescence in onset of gastric mucosal injury induced by hemorrhagic shock in rats.

In an attempt to clarify whether gastric mucosal autofluorescence can help us to recognize gastric lesions at the onset of their formation, we investigated the fluorescence generated from the gastric mucosa of rats under ischemia-reperfusion stress. Red-colored fluorescence appeared and began to increase within 5 min after reperfusion. Such an increase in fluorescence did not occur in the gastric mucosa under prolonged ischemia without reperfusion. The epifluorescence microscopy of mucosal cryosections revealed that fluorescence was present even when only superficial mucosal damage occurred. Spectrofluorometric and high-performance liquid chromatographic analysis of the fluorescent mucosa extract identified the fluorescent substances as porphyrins. These findings suggested that fluorescent porphyrins are generated in the mucosal layer during the introductory phase of mucosal lesion formation induced by ischemia-reperfusion stress.