The Relative Protective Effects of Moderate Dietary Restriction versus Dietary Modification on Spontaneous Cardiomyopathy in Male Sprague-Dawley Rats

The relative protective effects of modifying dietary protein, fat, fiber, and energy content vs moderate food or dietary restriction (DR) on spontaneous cardiomyopathy of Charles River male Sprague-Dawley (SD) rats was evaluated at 1 and 2 years. For 2 years, SD rats were fed Purina Rodent Chow 5002 (21.4% protein, 5.7% fat, 4.1% fiber, 3.1 kcal/g) or a modified rodent chow 5002-9 (13.6% protein, 4.6% fat, 15.7% crude fiber, 2.4 kcal/g) ad libitum (AL) or by moderate DR at approximately 65% of the caloric intake of the AL group fed the 5002 diet. Serum lipids, carcass composition, and organ weights were evaluated and hearts were qualitatively and quantitatively examined microscopically for male SD rats at 1 and 2 years. Cardiomyopathy was characterized by the colocalization of myocardial degeneration, the development of subepicardial, perivascular, subendocardial, and interstitial fibrosis, and mononuclear inflammatory cell infiltration that increased by incidence and severity in an age-dependent manner f...