Immunohistochemical localization of copper-zinc and manganese superoxide dismutases in rat tissues.

Abstract

Immunolocalization of both copper-zinc (CuZn) and manganese (Mn) superoxide dismutases (SODs) in various formalin-fixed rat tissues was investigated using the indirect immunoenzyme method. The optimal dilution was 1:10000 for rabbit anti-rat CuZnSOD and 1:5000 for anti-rat MnSOD antisera, respectively. The higher dilutions of the present antisera than those used in previous studies enabled a higher resolution of the present immunostaining because of a lower background staining. Neither SOD have been previously reported to be stained in eyeballs and brain. The following tissues were intensely stained for CuZnSOD: the fundic glands of the stomach, epithelium of the large intestine, tracheal and bronchial epithelia, liver parenchymal cells, proximal tubules and papillary ducts of the kidneys, pancreatic ducts and islets, zona glomerulosa of the adrenals, myocardial cells, ciliary bodies and pigment cell layers of retinas. On the other hand, the MnSOD activity was found to be rich in the following tissues: the gastric pits, epithelium of the small intestine, tracheal epithelium, Henle''s loop and collecting ducts of the kidneys, zona fasciculata of the adrenals, ciliary bodies and inner plexiform layer of retinas, and cortical neurons. The surface epithelia of both gastrointestinal and respiratory tracts tended to have high reactivities for both SODs, suggesting that the antioxidant enzyme defense system in these tissues responded to the exposure to superoxide generated from environmental oxygen. There was a wide range of variability in the distribution of each SOD from cell to cell. The present technique is thus considered to be useful for revealing site-specific changes in SODs in various rat tissues.