Localization of Exogenous Superoxide Dismutase in Myocardial Cells
Date
1990-12
Authors
Hamby, Rhoda L.
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Abstract
Free-radical formation injures myocardium upon reperfusion after a short episode of ischemia, and this injury can be reduced by provision of exogenous bovine Cu-Zn superoxide dismutase (SOD) and catalase (CAT). To determine the distribution of exogenous SOD infused into heart tissue, rabbits were immunized to SOD and antibodies isolated by affinity chromatography. Previous work in our laboratory had shown that rabbit antibodies prepared to bovine liver Cu-Zn SOD do not bind endogenous rat heart SOD.
Isolated working rat hearts were subjected to 15 minutes regional ischemia followed by up to 3 hours of reperfusion, with and without exogenous SOD+CAT in the perfusate. Hearts were removed at intervals and fixed in 4% paraformaldehyde. Vibratome sections of these hearts were treated with the rabbit anti-SOD, then with peroxidase conjugated anti-rabbit IgG. The peroxidase treated tissue was then exposed to diaminobenzidine (DAB) and H2Qg, followed by silver intensification of the resulting DAB polymer. The vibratome sections were examined by light microscopy or refixed, embedded, sectioned and examined by electron microscopy.
Anti-SOD binding was observed only in sections of hearts which were treated with exogenous SOD and subjected to ischemia followed by reperfusion. In these hearts, anti-SOD binding was apparent on capillary endothelial membranes and on the sarcolemma, the sarcoplasmic reticulum, and mitochondrial membranes of myocytes. This indicates transport of SOD from the capillary into myocytes does occur, and this transport is triggered by an episode of ischemia followed by reperfusion.
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Keywords
superoxide dismutase, catalase, ischemia
Citation
Hamby, R. L. (1991). Localization of exogenous superoxide dismutase in myocardial cells (Unpublished thesis). Southwest Texas State University, San Marcos, Texas.