Influence of dietary polyinsatured fatty acids on contractility,lusitropy and compliance of isolated rat myocardium

International audienc

Correlation between direct ESR spectroscopic measurements and electromechanical and biochemical assessments of exogenous free radical injury in isolated rat cardiac myocytes

58 ref. 2 tables 6 graph.International audienc

?-tocopherol concentrations, lipid peroxidation and superoxide dismutase and glutathione peroxidase activities in rat heart and liver after feeding stabilized and unstabilized fish oil

To further examine the relationship between increased consumption of n-3 polyunsaturated fatty acids (PUFAs), antioxidant defence systems and lipid peroxidation, for 6 weeks adult male rats were fed fish oil (FO)-rich diets containing one of two levels of ?-tocopherol (4.5 or 1.9 IU vitamin E/g fish oil) either with or without the addition of the antioxidant mix PUFANOX(R) in order to stabilize the FO; rats fed corn oil or butter served as controls. Feeding FO resulted in increased proportions of the n-3 PUFAs eicosapentaenoic and docosahexaenoic acids in the phospholipids of the plasma, myocardium and liver. Rats fed the PUFANOX(R)-stabilized FO had higher plasma, myocardial and liver ?-tocopherol concentrations compared to those fed the unstabilized FO; -tocopherol concentrations were highest in rats fed the higher level of -tocopherol in combination with PUFANOX(R). FO feeding increased lipid peroxidation in myocardial and liver extracts. This was highest after feeding the FO diet which contained the lower amount of ?-tocopherol and no PUFANOX(R) and was positively correlated with the n-3 PUFA content of the phospholipids. FO feeding did not alter myocardial and liver superoxide dismutase activity. Myocardial glutathione peroxidase activity was lower after feeding FO, except that containing the higher amount of -tocopherol plus PUFANOX(R). Glutathione peroxidase activity in the liver was lower after FO feeding than after corn oil with no significant differences among the different FO diets. Thus, insufficient antioxidant protection in FO results in decreased antioxidant defences and increased lipid peroxidation. Increasing the content of ?-tocopherol and including a stabilizing agent (e.g. PUFANOX(R)) in FO can prevent at least some of these effects. The results of the present study do not support the idea that intake of FO, by increasing tissue lipid peroxidation, induces the body's antioxidant defence system.<br/

Chronological and physiological ageing in a polar and a temperate mud clam

We investigated chronological and physiological ageing of two mud clams with regard to the rate of living theory (Pearl, 1928) and the free radical theory of ageing (Harman, 1956). The Antarctic Laternula elliptica (Pholadomyoida) and the temperate Mya arenaria (Myoida) represent the same ecotype (benthic infaunal filter feeders), but differ in maximum life span, 36 and 13 years, respectively. L. elliptica has a two-fold lower standard metabolic rate than M. arenaria, but its life long energy turnover at maximal age is three times higher. When comparing the two species within the lifetime window of M. arenaria, antioxidant capacities (glutathione, catalase) are higher and tissue oxidation (ratio of oxidised to reduced glutathione, lipofuscin accumulation) is lower in the polar L. elliptica than in the temperate mud clam. Tissue redox state in L. elliptica remained stable throughout all ages, whereas it increased dramatically in aged M. arenaria. Our results indicate that metabolic rates and maintenance of tissue redox state are major factors determining maximum lifespan in the investigated mud clams