Transgenic mitochondrial superoxide dismutase and mitochondrially targeted catalase prevent antiretroviral-induced oxidative stress and cardiomyopathy

Abstract

Transgenic mice (TG) were used to define mitochondrial oxidative stress and cardiomyopathy (CM) induced by zidovudine (AZT), an antiretroviral used to treat HIV/AIDS. Genetically engineered mice either depleted or overexpressed mitochondrial superoxide dismutase (SOD2 / KOs and SOD2-OX, respectively) or expressed mitochondrially targeted catalase (mCAT). TGs and wild-type (WT) littermates were treated (oral AZT, 35 days). Cardiac mitochondrial H 2 O 2, aconitase activity, histology and ultrastructure were analyzed. Left ventricle (LV) mass and LV end-diastolic dimension were determined echocardiographically. AZT induced cardiac oxidative stress and LV dysfunction in WTs. Cardiac mitochondrial H 2 O 2 increased and aconitase was inactivated in SOD2 / KOs, and cardiac dysfunction was worsened by AZT. Conversely, the cardiac function in SOD2-OX and mCAT hearts was protected. In SOD2-OX and mCAT TG hearts, mitochondrial H 2 O 2, LV mass and LV cavity volume resembled corresponding values from vehicle-treated WTs. AZT worsens cardiac dysfunction and increases mitochondrial H 2 O 2 in SOD2 / KO. Conversely, both SOD2-OX and mCAT TGs prevent or attenuate AZT-induced cardiac oxidative stress and LV dysfunction. As dysfunctional changes are ameliorated by decreasing and worsened by increasing H 2 O 2 abundance, oxidative stress from H 2 O 2 is crucial pathogenetically in AZT-induced mitochondrial CM. © 2009 USCAP, Inc.