Altered Ca2+ handling may be responsible for the development of cardiac contractile dysfunctions with advanced age. In the present study, we investigated the roles of oxidative damage to sarcoplasmic reticulum (SR) and expression of Ca2+-ATPase (SERCA 2a) and phospholamban in age-associated dysfunction of cardiac SR. SR vesicles were prepared from hearts of 2-, 6-, 15-, and 26-month-old Wistar rats. Although activity of Ca2+-ATPase decreased with advancing age, no differences in relative amounts of SERCA 2a and phospholamban protein were observed. On the other hand, significant accumulation of protein oxidative damage occurred with aging. The results of this study suggest that agerelated alteration in Ca2+-ATPase activity in the rat heart is not a consequence of decreased protein levels of SERCA 2a and phospholamban, but could arise from oxidative modifications of SR proteins. Cellular oxidative damage caused by reactive oxygen species could contribute to age-related alternations in myocardial relaxation., E. Babušíková ... [et al.]., and Obsahuje seznam literatury
The oxidative stress hypothesis of aging suggests that accumulation of oxidative damage is a key factor of the alterations in physiological function during aging. We studied age-related sensitivity to oxidative modifications of proteins and lipids of cardiac sarcoplasmic reticulum (SR) isolated from 6-, 15- and 26-month-old rats. Oxidative stress was generated in vitro by exposing SR vesicles to 0.1 mmol/l FeSO4/EDTA + 1 mmol/l H2O2 at 37 °C for 60 min. In all groups, oxidative stress was associated with decreased membrane surface hydrophobicity, as detected by 1-anilino-8-naphthalenesulfonate as a probe. Structural changes in SR membranes were accompanied by degradation of tryptophan and significant accumulation of protein dityrosines, protein conjugates with lipid peroxidation products, conjugated dienes and thiobarbituric acid reactive substances. The sensitivity to oxidative damage was most pronounced in SR of 26-month-old rat. Our results indicate that aging and oxidative stress are associated with accumulation of oxidatively damaged proteins and lipids and these changes could contribute to cardiovascular injury., E. Babušíková, M. Jeseňák, D. Dobrota, N. Tribulová, P. Kaplán., and Obsahuje bibliografii a bibliografické odkazy
Mitochondrial dysfunction and accumulation of oxidative damage have been implicated to be the major factors of aging. However, data on age-related changes in activities of mitochondrial electron transport chain (ETC) complexes remain controversial and molecular mechanisms responsible for ETC dysfunction are still largely unknown. In this study, we examined the effect of aging on activities of ETC complexes and oxidative damage to proteins and lipids in cardiac mitochondria from adult (6-month-old), old (15-month-old) and senescent (26-month-old) rats. ETC complexes I-IV displayed different extent of inhibition with age. The most significant decline occurred in complex IV activity, whereas complex II activity was unchanged in old rats and was only slightly reduced in senescent rats. Compared to adult, old and senescent rat hearts had significantly higher levels of malondialdehyde, 4-hydroxynonenal (HNE) and dityrosine, while thiol group content was reduced. Despite marked increase in HNE content with age (25 and 76 % for 15-and 26-month-old rats, respectively) Western blot analysis revealed only few HNE-protein adducts. The present study suggests that non-uniform decline in activities of ETC complexes is due, at least in part, to mitochondrial oxidative damage; however, lipid peroxidation products appear to have a limited impact on enzyme functions., Z. Tatarková ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Oxidative stress has been implicated to play a major role in aging and age-related diseases. In the present study, we investigated the effects of aging on the total antioxidant capacity, uric acid, lipid peroxidation, total sulfhydryl group content and damage to DNA in adult (6 months), old (15 months) and senescent (26 months) male Wistar rats. The antioxidant capacity, determined by phycoerythrin-based TRAP method (total peroxyl radical-trapping potential) was significantly decreased in the plasma and myocardium of old and senescent rats, whereas plasma level of uric acid was elevated in 26-month-old rats. Age-related decline in plasma and heart antioxidant capacity was accompanied by a significant loss in total sulfhydryl group content, increased lipid peroxidation and higher DNA damage in lymphocytes. Correlations between TRAP and oxidative damage to lipids, proteins and DNA suggest that the decline in antioxidant status may play an important role in age-related accumulation of cell damage caused by reactive oxygen species., M. Sivoňová, Z. Tatarková, Z. Ďuračková, D. Dobrota, J. Lehotský, T. Matáková, P. Kaplán., and Obsahuje bibliografii a bibliografické odkazy