Endoscopic Fluorescence Observation of Gastric Mucosa After Indomethacin Treatment in Rats

Background and Study Aims: The present authors have already reported that mucosal autofluorescence intensity was increased in gastric lesions induced by nonsteroidal anti-inflammatory drugs. The aim of this study was to clarify whether the observation of mucosal autofluorescence with a newly established endoscopic fluorescence analyzing system could help us to recognize indomethacin-induced gastric lesion formation in vivo.

Materials and Methods: Gastric mucosal fluorescence intensity was measured time-sequentially after indomethacin treatment in rats, using a fluorescence endoscope system. The concentration of thiobarbituric acid-reactive substances in gastric mucosa was measured as an indicator of tissue lipid peroxidation. Fluorescent substances from rat stomachs were analyzed using high performance liquid chromatography.

Results: Treatment with indomethacin induced a time-dependent increase of fluorescence intensity. The concentration of thiobarbituric acid-reactive substances was also increased after the treatment. Pretreatment with radical scavenging reagent constrained the increase of both the fluorescence intensity and the concentration of thiobarbituric acid-reactive substances. The fluorescence products were coproporphyrin, protoporphyrin and mesoporphyrin.

Conclusions: These findings indicate that the intensity of porphyrin fluorescence increased in gastric mucosal lesions induced by oxygen radicals. Endoscopic observation of mucosal fluorescence was shown to aid the sensitive and objective diagnosis of gastric injuries.

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