Manganese superoxide dismutase and reduced nicotinamide adenine dinucleotide diaphorase colocalize in the rat gut.

Abstract

Superoxide and other free radicals participate in inflammatory bowel disease and ischemia-reperfusion injury. Manganese superoxide dismutase (SOD) scavenges superoxide. Mn SOD is colocalized with reduced nicotinamide adenine dinucleotide (NADH) diaphorase in some tissues. NADH diaphorase histochemistry selectively stains enteric nerves. The aim of this study was to seek colocalization of Mn SOD with NADH diaphorase in the gut, especially in enteric nerves. Indirect immunofluorescent staining and histochemistry were used to localize Mn SOD and NADH diaphorase in rat gut. Strong Mn SOD immunoreactivity was found in parietal cells, most intramural nerve cell bodies, the colonic interstitial cells of Cajal (at the submucosa-circular muscle layer interface), and intestinal epithelium cells. Weak to moderate Mn SOD immunoreactivity characterized smooth muscle cells, small submucosal arteries, esophageal striated muscle, esophageal epithelium, gastric epithelium, and intestinal glands. NADH diaphorase histochemistry (with Triton X-100) resulted in identical staining. Mn SOD and NADH diaphorase are colocalized throughout rat gut with strong activity in enteric nerves and colonic interstitial cells of Cajal.