Effects of n−3 and n−6 fatty acids on the activities and expression of hepatic antioxidant enzymes in autoimmune‐prone NZB×NZW F₁ mice

Abstract

Menhaden fish oil (FO) containing n-3 fatty acids dramatically extends the life span and delays the onset and progression of autoimmune disease in (NZBxNZW)F1 (B/W) female mice as compared to those fed corn oil (CO) rich in n-6 lipids. As an inefficient antioxidant defense system has been linked to autoimmune diseases, the present study was undertaken to determine whether the protective action of n-3 lipids is mediated through their antioxidant defense system. Weanling B/W mice were fed a nutritionally adequate, semipurified diet containing CO or krill oil (KO) or FO at 10% level (w/w) ad libitum until the mice were 6.5 months old. All diets contained the same level of vitamin E (21.5 mg/100 g diet). We compared the effects of feeding n-6 and n-3 lipids on survival, kidney disease, hepatic microsomal lipid composition, peroxidation, and on the activity and mRNA expression of the antioxidant enzymes catalase, glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) in 6.5-month-old B/W mice. The results showed that when compared to livers from CO-fed mice, livers from KO- and FO-fed mice showed: (i) significantly higher (P < 0.001) activities and expression of CAT, GSH-Px and SOD; (ii) significantly lower (P < 0.001) arachidonic acid (20:4n-6) and linoleic acid (18:2n-6) and higher (P < 0.001) eicosapentaenoic acid (20:5n-3) and docosahexaenoic acid (22:6n-3) levels in hepatic microsomes; and (iii) significantly lower (P < 0.001) estimated peroxidation indices and thiobarbituric acid reactive substances generation.(ABSTRACT TRUNCATED AT 250 WORDS)

Induction of proinflammatory cytokine and antioxidant enzyme gene expression following brief myocardial ischaemia

“…A 10-min centrifugation at 2000 g replaced the lengthy organic solvent extraction of pigments [13]. Malondialdehyde (as tetraethyl acetal; Aldrich Chemical Co., Milwaukee, WI) was used as a standard.…”

Effects of calorie restriction and ω-3 dietary fat on aging in short-and long-lived rodents

“…In both liver and spleen, we found that fish oil feeding suppressed expression of message for these enzymes (61,64). In the liver, antioxidant enzyme activity was determined, and also found to be higher in fish oil fed animals.…”

The effects of dietary lipids on gene expression and apoptosis

“…Mice on both FO and CO gained the same amount of weight (40-45 g). Northern blot analysis of kidney extracts from 6-month-old FO-fed mice revealed no detectable levels of IL-10, IL-6, and TNF-a mRNA, whereas these cytokine mRNA were easily detected in 6-month-old CO-fed mice (Chandrasekar & Fernandes, 1994). In contrast to the cytokine mRNA, FO-fed mice showed higher renal levels of the antioxidant enzymes catalase (EC 1.1 1.1.6), glutathione peroxidase (EC 1.1 1.1.9), and superoxide dismutase (EC 1.15.…”

“…Furthermore, significantly lower estimated peroxidation indices and generation of thiobarbituric acidreactive substances were noted in FO-fed mice. These findings suggest that one of the mechanisms by which the n-3 lipids may delay the onset of autoimmune disease could be through the maintenance of higher hepatic antioxidant enzyme expression and activity levels (Venkatraman et al 1994).…”

“…I . 1) compared with CO-fed mice (Chandrasekar & Fernandes, 1994). These data indicated that dietary supplementation with FO, compared with CO, may suppress pro-inflammatory cytokine production, which in turn could ameliorate immune-complex-mediated kidney injury by enhancing the ability of cells to dispose of harmful reactive oxygen intermediates (Chandrasekar & Fernandes, 1994).…”