title: Cardiac responses of rats submitted to postnatal protein restriction.
abstract: 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.
authors.affiliation: Universidade Federal de Minas Gerais, Belo Horizonte 31.270-901, MG, Brazil.
authors.forename: Tatiane Moisés
authors.initials: TM
authors.lastname: Murça
authors.forename: Tatiana Soares Dos Reis
authors.initials: TS
authors.lastname: Magno
authors.forename: Marilda Luz de Andrade
authors.initials: ML
authors.lastname: De Maria
authors.forename: Carolina Andrade Bragança
authors.initials: CA
authors.lastname: Capuruço
authors.forename: Deoclécio Alves
authors.initials: DA
authors.lastname: Chianca
authors.forename: Anderson José
authors.initials: AJ
authors.lastname: Ferreira
mesh_terms: D000320:Adrenergic Fibers; D000704:Analysis of Variance; D000818:Animals; D001794:Blood Pressure; D006332:Cardiomegaly / Q000097:blood / Q000000981:diagnostic imaging; D004032:Diet / Q000379:methods; D018753:Diet, Protein-Restricted / Q000379:methods*; D004195:Disease Models, Animal; D006321:Heart / Q000503:physiopathology*; D006331:Heart Diseases / Q000097:blood / Q000000981:diagnostic imaging*; D006334:Heart Function Tests / Q000379:methods*; D006339:Heart Rate; D006352:Heart Ventricles / Q000000981:diagnostic imaging; D008297:Male; D011502:Protein-Energy Malnutrition / Q000097:blood / Q000503:physiopathology*; D051381:Rats; D017208:Rats, Wistar; D014463:Ultrasonography; D016277:Ventricular Function, Left; D020257:Ventricular Remodeling