The protective role of copper-zinc superoxide dismutase against alloxan-induced diabetes: morphological aspects

Abstract

Copper-zinc Superoxide dismutase is known to protect pancreatic β-cell function from the damage of alloxan. A morphological investigation of copper-zinc Superoxide dismutase prophylaxis against alloxan was undertaken in rats to investigate the mechanism of this protective action. Exogenous copper-zinc Superoxide dismutase reproducibly protected the morphological features of pancreatic β cells against damage by alloxan as determined by light microscopic immunostaining for insulin and by ultrastructural examination. By the same criteria, α and δ cells appeared unaffected by administration of a combination of alloxan and copper-zinc superoxide dismutase or either agent alone. Autoradiography after injection of ¹²⁵I labelled copper-zinc superoxide dismutase into normal rats showed no evidence that the enzyme enters viable islet cells, suggesting an extracellular site of protection against alloxan.