Alloxan and lactic acid dehydrogenase activity of the cornea.

THE complex problem of corneal vascularization has excited the interest of several investigators for many years, and it is generally believed that positive chemotaxis is the primary stimulus to neovascularization, both chemical and physical trauma being considered as potentiating factors. Low oxygen tensions are conducive to neovascularization, so that the role of localized anoxia and the resulting accumulation of certain metabolites must also be considered (Ashton and Cook, 1953); these authors review the possibilities, and also stress the importance of the removal of physical or mechanical obstruction, as originally pointed out by Cogan (1949). Thus oedema, by decreasing the corneal compactness, plays a fundamental role. Langham (1953) induced vascularization in the cornea of rabbits by injecting alloxan intracamerally, but more recently Graymore and McCormick (1968) have shown that alloxan may be applied directly to the surface of the cornea with equal success. This method, among other advantages, avoids mechanical trauma. As a preliminary to the present study, the content, nature, and distribution of the enzyme lactic acid dehydrogenase (LDH) was studied in detail in the normal cornea (Graymore, 1966; Graymore and McCormick, 1966) and this communication reports certain changes observed after treating the cornea with alloxan.