CONICET | Buscador de Institutos y Recursos Humanos

Increasing evidence from different experimental models supports the concept that oxidative stress contributes to the pathogenesis of myocardial hypertrophy and in the process of myocardial remodeling leading to heart failure. On the other hand, oxidative stress appears implicated in the ageing. Oxidative stress is the result of an increase of reactive oxygen species (ROS) production and/or inadequate antioxidant defense mechanisms. Taking into account that the existing data about the antioxidant status of hypertension are inconsistent, our goal was to assess the oxidative stress in hearts from young and old spontaneously hypertensive rats (SHR) compared to age-matched Wistar (W) rats. To fulfill this goal we measured thiobarbituric acid reactive substances (TBARS) to estimate the lipid peroxidation, protein nitration, superoxide production, NAD(P)H activity and superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) enzyme activities in hearts from both rat strains of 4 and 19-month-old. We obtained that TBARS and nitrotyrosine levels were similar in young SHR and W rats but significantly increased with ageing, showing SHR higher values than age-matched W rats. NAD(P)H activity and superoxide production in young SHR and W rats were similar but it were higher in aged SHR compared with age-matched W. CAT activity increased in hearts of 4-month-old SHR compared to age-matched W rats and decreased in the oldest. SOD and GPx activities decreased in both rat strains with ageing. Our data show that: 1) SHR and W young rats showed similar oxidative damage and 2) aged SHR exhibited higher levels of oxidative damage than age-matched W rats, probably related to the increase in NAD(P)H oxidase activity and superoxide production detected in that rat strain.