Cardiac responses of rats submitted to postnatal protein restriction

• Published in: Applied physiology, nutrition, and metabolism Vol. 37; no. 3; pp. 455 - 462
• Main Authors: Murça, Tatiane Moisés, Magno, Tatiana Soares dos Reis, De Maria, Marilda Luz de Andrade, Capuruço, Carolina Andrade Bragança, Chianca, Deoclécio Alves, Ferreira, Anderson José
• Format: Journal Article
• Language: English
• Published: Canada NRC Research Press 01.06.2012; Canadian Science Publishing NRC Research Press
• Subjects: Adrenergic Fibers; Analysis; Analysis of Variance; Animal subjects; Animals; Blood Pressure; Cardiac function; cardiac output; Cardiomegaly - blood; Cardiomegaly - diagnostic imaging; Cardiorespiratory; Cardiovascular disease; childhood; cœur isolé; Diet; Diet (effects); Diet - methods; Diet, Protein-Restricted - methods; Disease Models, Animal; Echocardiography; fibres noradrénergiques; fonction cardiaque; Health aspects; Heart; Heart - physiopathology; Heart Diseases - blood; Heart Diseases - diagnostic imaging; heart function; Heart Function Tests - methods; Heart Rate; Heart Ventricles - diagnostic imaging; hematologic tests; homeostasis; human population; hypertrophy; isolated hearts; Low-protein diet; Male; males; malnutrition; metabolism; noradrenergic fibers; Nutrition; Physiological aspects; Physiology; Protein-Energy Malnutrition - blood; Protein-Energy Malnutrition - physiopathology; Proteins; Rats; Rats, Wistar; Rodents; régime hypoprotéiné; sous-nutrition; Techniques; Ultrasonography; undernutrition; Ventricular Function, Left; Ventricular Remodeling; échocardiographie; Brazil
• ISSN: 1715-5312; 1715-5320; 1715-5320
• DOI: 10.1139/h2012-017

Undernutrition during critical stages of development and childhood has important effects on cardiovascular homeostasis. The present study was undertaken to evaluate the in vivo and ex vivo cardiac function of rats submitted to postnatal protein restriction. Male Wistar rats (28 days old) were fed a regular (20%) or low-protein (6%) diet over 5 weeks. After this period, cardiac function was analyzed by echocardiography and isolated heart preparation. Furthermore, the density of cardiac noradrenergic fibers and hematological profile were evaluated. We found that malnourished rats exhibited elevated arterial blood pressure, increased fractional shortening (echocardiography), increased systolic tension, increased ±dT/dt (isolated heart technique), impaired diastolic function characterized by a slight increase in the left ventricular end-diastolic diameter (echocardiography) and decreased diastolic tension (isolated heart technique), and cardiac hypertrophy evidenced by augmentation of the posterior left ventricular wall and discrete hematological changes. In addition, malnourished rats exhibited increased noradrenergic fiber density in their hearts (0.08% ± 0.02% area in control rats vs. 0.17% ± 0.03% area in malnourished rats). Our current data demonstrate that postnatal protein restriction causes cardiac adaptation characterized by an early overworking heart. This is at least in part mediated by an increase in the efferent sympathetic fibers to the heart. These findings provide important information for efforts to prevent and manage the consequences of undernutrition in the human population.