NADPH-Oxidase activity and lipid peroxidation in neutrophils from rats fedfat-rich diets

In order to investigate the effect of fat-rich diets on neutrophil function s, 21 day-aged rats were fed for 6 weeks with a control diet consisting of a regular laboratory rodent chow (4 per cent final fat content), a control diet supplied with soybean oil (15 per cent final fat content), or a contro l diet supplied with coconut oil (15 per cent final fat content). Glycogen- elicited peritoneal neutrophils from rats fed soybean and coconut oil-enric hed diets presented a reduction in spontaneous and PMA-stimulated H2O2 gene ration relative to neutrophils from rats fed the control diet. The activity of superoxide dismutase, glutathione peroxidase and catalase did not chang e in animals fed fat-rich diets. In addition, the capacity to generate O-2( .-), spontaneously or in response to PMA, did not change in neutrophils fro m animals fed fat-rich diets. Values attained matched those observed in ani mals fed the control diet, regardless of the method used to measure O-2(.-) , the superoxide dismutase-inhibitable reduction of cytochrome c or the luc igenin-dependent chemiluminescence. However, the initial rate of O-2(.-) ge neration both in resting neutrophils and in PMA-stimulated cells was signif icantly reduced when animals were fed with coconut or soybean oil-enriched diets due, at least in part, to a reduction in the activity of glucose-6-ph osphate dehydrogenase. The concentration of thiobarbituric acid reactive su bstances, an index of lipid peroxidation, was increased in animals fed both fat-rich diets. This was accompanied by an increase in arachidonic acid co ntent in these cells. Results presented suggest that lipid peroxidation in neutrophils from animals fed fat-rich diets may be associated with a consum ption of H2O2 yielding more reactive oxygen-derived species such as the hyd roxyl radical. Copyright (C) 1999 John Wiley & Sons, Ltd.