Oxidative stress caused by excessive reactive species (RS) and lipid peroxidation is known to be casually linked to age-related
inflammation. To test the hypothesis that
fish oil (FO) intake has a beneficial effect on
nephritis due to its suppressive action of oxidative stress and the enhancement of
antioxidant defenses, we examined the effect of dietary FO on various oxidative stress-related parameters and guanidino compound (GC) levels using (NZB x NZW) F1 (B/W) mice. These mice were fed diets supplemented with either 5%
corn oil (control) or 5% FO. At 4 and 9 months of age, the hepatic oxidative status was estimated by assessing RS generation produced from
xanthine oxidase, the
prostaglandin pathway and lipid peroxidation. To evaluate the effect of FO on redox status, including
antioxidant defenses, GSH and
GSSG levels and
antioxidant enzyme activities were measured. To correlate the extent of oxidative status with the nephritic condition,
creatinine, guanidino
acetic acid and
arginine levels were measured. Results indicated that increased levels of lipid peroxidation, RS generation and
xanthine oxidase activity with age were all significantly suppressed by FO feeding. Furthermore, reduced GSH levels, GSH/
GSSG ratio and
antioxidant enzyme activities in the FO-fed mice were effectively enhanced compared to the
corn oil-fed mice. Among several GCs, the age-related increase of
creatinine level was blunted by FO. Based on these results, we propose that dietary FO exerts beneficial effects in aged, nephritic mice by suppressing RS,
superoxide and lipid peroxidation, and by maintaining a higher GSH/
GSSG ratio and
antioxidant enzyme activities.