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Conti, Marc, Isabelle M. Renaud, Bruno Poirier, Odile Michel, Marie-France Belair, Chantal Mandet, Patrick Bruneval, Isaac Myara, and Jacques Chevalier. High levels of myocardial antioxidant defense in aging nondiabetic normotensive Zucker obese rats. Am J Physiol Regul Integr Comp Physiol 286: R793-R800, 2004. First published December 11, 2003; 10.1152/ajpregu.00521.2002.--Chronic renal failure often induces left ventricular hypertrophy. We assessed whether the heart is affected in the Zucker obese rat, a model of chronic renal failure associated with obesity, glucose intolerance, and insulin resistance without hypertension or hyperglycemia. After systemic blood pressure measurement, the heart, the aorta, and the kidneys were removed from anesthetized 9- and 13-mo-old Zucker obese and lean control male rats (n = 33, n = 24, n = 25, and n = 21, respectively). Determination of left ventricular geometry, quantification of myocardium collagen density, and measurement of heart antioxidant enzyme activity were made, as well as aorta and kidney parameters. Mean blood pressure remained at a normal range whatever the age and group considered. Whereas kidney structure and function were severely impaired, no sign of myocardial infarction or inflammatory process was noticed. A moderate left ventricular hypertrophy was observed in 13-mo-old obese rats. While heart malondialdehyde was stable with age and among groups, antioxidant enzyme activity was higher in obese rats. In conclusion, in the absence of hypertensive or hyperglycemic disorders, the heart seems to display a sufficient line of defense against oxidative stress during the development of cardiac hypertrophy. left ventricular hypertrophy; renal failure; oxidative stress; Zucker rats; hyperlipidemia

Obese Zucker rat model helps examine the long-term effect of hyperinsulinemia on the migration and proliferation of aortic smooth muscle cell (SMC) induced by arterial injury with a balloon catheter. Long-lasting hyperinsulinemia induces SMC proliferation after diendothelialization, leading to higher aortic thickening in obese rats than that in lean rats. Biochemical techniques facilitate the quantitative determination of SMC proliferation within the intima-media and histological morphometric measurements help differentiate the modifications in intimal and medial cross-sectional areas and also in the number of nuclei.