Protein restriction after weaning modifies the calcium kinetics and induces cardiomyocyte contractile dysfunction in rats.

Penitente, Arlete Rita; Novaes, Rômulo Dias; Chianca Júnior, Deoclécio Alves; Silva, Márcia Ferreira da; Silva, Marcelo Eustáquio; Souza, Aline Maria Arlindo de; Fonseca, Silvia Carolina Guatimosim; Almeida, Pedro William Machado de; Alves, Márcia Netto Magalhães; Felix, Leonardo Bonato; Neves, Clóvis Andrade; Natali, Antônio José

Protein restriction after weaning modifies the calcium kinetics and induces cardiomyocyte contractile dysfunction in rats.

Date

2013

Authors

Penitente, Arlete Rita

Novaes, Rômulo Dias

Chianca Júnior, Deoclécio Alves

Silva, Márcia Ferreira da

Silva, Marcelo Eustáquio

Souza, Aline Maria Arlindo de

Fonseca, Silvia Carolina Guatimosim

Almeida, Pedro William Machado de

Alves, Márcia Netto Magalhães

Felix, Leonardo Bonato

Abstract

Protein restriction (PR) is associated with cardiovascular diseases. The purpose of this study was to investigate the effects on single ventricular cardiomyocyte contractile function of a short-term PR after weaning. Male Fischer rats that were 28 days old were randomly divided into a control group (CG, n = 16) and a protein-restricted group (PRG, n = 16). After weaning, CG and PRG animals received isocaloric diets containing 15 and 6% protein, respectively, for 35 days. Biometric parameters were then measured, and the hearts were removed for the analysis of contractile function and calcium transient in isolated cardiomyocytes of the left ventricule (LV), and the quantification of calcium and collagen fibers in LV myocardium. PRG animals had lower body weight (BW) and LV weight (LVW), an increased LVW to BW ratio and a higher proportion of collagen fibers than CG animals. PRG animals exhibited reduced tissue levels of calcium, reduced the length, width and volume of cardiomyocytes and their sarcomere length compared to CG animals. Cardiomyocytes from PRG animals had a lower amplitude of shortening, a slower time to the peak of shortening and a longer time to half-relaxation than those from the CG. Cardiomyocytes from PRG animals also presented a lower peak of calcium transient and a longer calcium transient decay time than CG animals. Taken together, the results indicate that short-term PR after weaning induces a marked structural remodeling of the myocardium parenchyma and stroma that coexists with contractile dysfunctions in single LV cardiomyocytes of rats, which is probably associated with pathological changes of the intracellular calcium kinetics, rather than inadequate available amounts of this mineral in cardiac tissue.

Keywords

Malnutrition, Cardiovascular system, Calcium transient

Citation

PENITENTE, A. R. et al. Protein restriction after weaning modifies the calcium kinetics and induces cardiomyocyte contractile dysfunction in rats. Cells Tissues Organs, v. 198, p. 311-317, 2013. Disponível em: <https://www.karger.com/Article/FullText/355943>. Acesso em: 19 fev. 2017.