title: Oxidative Damage in the Aging Heart: an Experimental Rat Model.
abstract: BACKGROUND
  Several theories have been proposed to explain the cause of 'aging'; however, the factors that affect this complex process are still poorly understood. Of these theories, the accumulation of oxidative damage over time is among the most accepted. Particularly, the heart is one of the most affected organs by oxidative stress. The current study, therefore, aimed to investigate oxidative stress markers in myocardial tissue of rats at different ages.
  
  
  METHODS
  Seventy-two rats were distributed into 6 groups of 12 animals each and maintained for 3, 6, 9, 12, 18 and 24 months. After euthanasia, the heart was removed and the levels of non-protein thiols, lipid peroxidation, and protein carbonylation, as well as superoxide dismutase and catalase activities were determined.
  
  
  RESULTS
  Superoxide dismutase, catalase activity and lipid peroxidation were reduced in the older groups of animals, when compared with the younger group. However, protein carbonylation showed an increase in the 12-month group followed by a decrease in the older groups. In addition, the levels of non-protein thiols were increased in the 12-month group and not detected in the older groups.
  
  
  CONCLUSIONS
  Our data showed that oxidative stress is not associated with aging in the heart. However, an increase in non-protein thiols may be an important factor that compensates for the decrease of superoxide dismutase and catalase activity in the oldest rats, to maintain appropriate antioxidant defenses against oxidative insults.
authors.affiliation: Internal Medicine Department - Universidade Federal do Paraná, Brazil.
authors.forename: Gustavo Lenci
authors.initials: GL
authors.lastname: Marques
authors.affiliation: Cell Biology Department - Universidade Federal do Paraná, Brazil.
authors.forename: Francisco Filipak
authors.initials: FF
authors.lastname: Neto
authors.affiliation: Cell Biology Department - Universidade Federal do Paraná, Brazil.
authors.forename: Ciro Alberto de Oliveira
authors.initials: CA
authors.lastname: Ribeiro
authors.affiliation: Cell Biology Department - Universidade Federal do Paraná, Brazil.
authors.forename: Samuel
authors.initials: S
authors.lastname: Liebel
authors.affiliation: Surgery Department - Universidade Federal do Paraná, Brazil.
authors.forename: Rogério
authors.initials: R
authors.lastname: de Fraga
authors.affiliation: Internal Medicine Department - Universidade Federal do Paraná, Brazil.
authors.forename: Ronaldo da Rocha Loures
authors.initials: Rda R
authors.lastname: Bueno
keywords: Aging; Catalase; Glutathione; Lipid Peroxidation; Protein Carbonylation; ROS; Rat; Superoxide Dismutase.