ASSESSMENT OF MICROVASCULAR INTEGRITY IN THE ISOLATED-PERFUSED RAT-LIVER BY CONTRAST-ENHANCED MRI - ATTENUATION OF REPERFUSION INJURY BY CONJUGATED DEFEROXAMINE

Reperfusion of an ischemic organ can lead to microcirculatory impairme nt caused, in part, by the generation of reactive free radicals. The i ron-catalyzed formation of these deleterious substances can be counter acted by strong metal chelators like deferoxamine. In this study, the protective effect of deferoxamine conjugate was evaluated by assessmen t of the hepatic microcirculation in the post-ischemic phase. Assessme nt of the microvasculature was performed by MRI on the isolated perfus ed rat liver. The restriction of sinusoids subsequent to reperfusion i njury was demonstrated by the use of a particulate superparamagnetic c ontrast agent trapped in the microvasculature. The protective effect o f conjugated deferoxamine was evaluated by both MRI and release of ala nine aminotransferase. Contrast-enhanced MRI demonstrated a marked imp airment of the microcirculation subsequent to the unprotected reperfus ion of the ischemic tissue. This injury was attenuated by deferoxamine conjugated to hydroxyethylstarch (HES-DFO).