Cardiac-specific overexpression of catalase prolongs survival and attenuates paraquat-induced myocardial contractile dysfunction

Paraquat, a quarternary nitrogen herbicide, is highly toxic for humans and animals via generation of reactive oxygen species. This study was designed to examine the influence of cardiac-specific overexpression of catalase (CAT), an antioxidant enzyme responsible for detoxification of H2O2 on murine myocardial contractile function following the challenge of the pro-oxidant paraquat. FVB and CAT mice were administrated paraquat (75 mg/kg) and myocardial function was monitored with echocardiography and edge-detection. Cardiomyocyte mechanical indices analyzed included peak shortening (PS), time-to-PS (TPS), time-to-90% relengthening (TR90), and maximal velocity of shortening/relengthening (+/-dL/dt). Our results revealed that CAT mice displayed a significantly improved survival against paraquat-induced death than FVB mice as evaluated by the Kaplan-Meier curve. The CAT transgene itself did not alter cardiac function. Paraquat treatment for 48 hours enlarged end-systolic diameter, reduced fractional shortenin...