Immunoelectron microscopic localization of copper-zinc superoxide dismutase in human gastric mucosa

Superoxide radicals appear to play important roles in the pathogenesis of various gastric mucosal lesions. To add to a greater understanding of the pathogenesis of the various gastric mucosal lesions caused by oxygen-derived free radicals, we examined the distribution of copper-zinc superoxide dismutase (Cu,Zn-SOD) in normal human gastric mucosa using a direct immunoperoxidase method under light and electron microscopy. Under light microscopy, we detected Cu,Zn-SOD in propria gland cells but not in foveolar cells of the fundic mucosa or in antral gland cells. With electron microscopy, Cu,Zn-SOD was detected in the ultrastructural morphology of parietal and chief cells. In parietal cells, it was present mainly in the cytoplasm, partially on the outer membrane of mitochondria, and in the nuclei, and in chief cells, in the cytoplasm. Our findings suggest that Cu,Zn-SOD plays important roles in scavenging oxygen radicals generated in the cytoplasm.