IS CARDIAC HYPERTROPHY IN SPONTANEOUSLY HYPERTENSIVE RATS ?

MARÍA C ÁLVAREZ; CLAUDIA CALDIZ; JULIANA C FANTINELLI; CAROLINA D GARCIARENA; GLORIA M CONSOLE; GLADYS E CHIAPPE DE CINGOLANI; MARÍA S MOSCA

HYPERTENSION RESEARCH

NATURE PUBLISHING GROUP

Año: 2008 vol. 31 p. 1465 - 1476

0916-9636

The aim of this work was to assess the possible correlation between oxidative damage and the developmentof cardiac hypertrophy in heart tissue from young (40-d-old) and older (4-, 11- and 19-month-old) spontaneouslyhypertensive rats (SHR) in comparison with age-matched Wistar (W) rats. To this end, levels ofthiobarbituric acid reactive substances (TBARS), nitrotyrosine contents, NAD(P)H oxidase activity, superoxideproduction, and the activities of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT)and glutathione peroxidase (GPx) were determined. Compared to age-matched normotensive rats, SHRshowed a significant increase in systolic blood pressure from 40 d of age and left ventricular hypertrophy(LVH) was significantly evident from 4 months of age. W rats (11- and 19-month-old) also showed anincrease in LVH with aging. TBARS and nitrotyrosine levels were similar in young rats from both strains andwere significantly increased with age in both strains, with the values in SHR being significantly higher thanthose in age-matched W rats. NAD(P)H activity was similar in young SHR and W rats, whereas it was higherin aged SHR compared with age-matched W rats. Compared to W rats, superoxide production was higherin aged SHR, and was abolished by NAD(P)H inhibition with apocynin. CAT activity was increased in thehearts of 4-month-old SHR compared to age-matched W rats and was decreased in the hearts of the oldestSHR compared to the oldest W rats. SOD and GPx activities decreased in both rat strains with aging. Moreover,an increase in collagen deposition with aging was evident in both rat strains. Taken together, thesedata showed that aged SHR exhibited higher cardiac hypertrophy and oxidative damage compared to W rats,indicating that the two undesirable effects are associated. That is, oxidative stress appears to be a causeand/or consequence of hypertrophy development in this animal model.