Dietary 18:3 and Long Chain n‐3 PUFA Protected Rats from Fructose‐Induced Oxidative and Endoplasmic Reticulum Stress in Visceral Adipose Tissue

Abstract

Effect of dietary n‐6/n‐3 polyunsaturated fatty acids (PUFA) ratio on the fructose‐induced adipose tissue oxidative and endoplasmic reticulum (ER) stress was not explored previously. Here, we studied the effect of diets containing n‐6 PUFA & α‐linolenic acid (ALA, 18:3 n‐3 PUFA) and n‐6 PUFA & long chain n‐3 PUFA (docosahexanoic acid and eicosapentaenoic acid, DHA and EPA) in the ratio of 2:1 and 5:1 respectively on fructose‐induced oxidative and ER stress in adipose tissue.Weanling Wistar rats were divided in to four groups and fed with diets containing starch (n‐6/n‐3 PUFA ratio 215:1), fructose (n‐6/n‐3 PUFA ratio 215:1) and fructose‐with n‐6/n‐3 PUFA ratio 2:1 (18:3 n‐3 PUFA) and 5:1 (long chain n‐3 PUFA) diets for twenty‐four weeks. Activities of glucose‐6‐phosphate dehydrogenase (G6PDH), glutathione peroxidase (GPx), and catalase and superoxide dismutase (SOD) were measured in visceral adipose tissue along with glutathione levels and lipid peroxidation. Expression of p22 phox gene related oxidative stress was quantified along with ER stress marker gene, GRP78.ALA and long chain (LC) n‐3 PUFA feeding significantly reduced fructose‐induced G6PDH activity to similar extent by 28% (p≤0.01). Both ALA and LC n‐3 PUFA significantly reduced the fructose‐induced SOD activity by 15% and 12% respectively (p≤0.01), whereas they reduced fructose‐induced catalase activity to similar extent by 23.5% (p≤0.05). ALA and long chain (LC) n‐3 PUFA feeding significantly elevated the GPx activity that is reduced by high fructose‐ diet feeding by 14.6% and 12% respectively (p≤0.05) without altering the tissue glutathione levels. Lipid peroxidation, an important determinant of tissue oxidative stress is significantly reduced by both ALA‐ and LC n‐3 PUFA‐enriched diets by 12% and 35% respectively (p≤0.01). p22 phox gene expression is significantly reduced by both ALA and LC n‐3 PUFA by 12% and 33% respectively (p≤0.05) along with ER stress marker, GRP78 by 40% and 30% respectively (p≤0.05).We conclude that replacement of dietary n‐6 PUFA with ALA and LC n‐3 PUFA ameliorates fructose‐induced oxidative and ER stress in visceral adipose tissue. Though both ALA and LC n‐ 3 PUFA significantly reduced fructose‐induced oxidative stress, considering beneficial effects LC n‐3 PUFA on lipid peroxidation and LC n‐3 PUFA exhibited protective nature at less quantity than ALA, we propose that diets rich in LC n‐3 PUFA may protect against fructose‐induced oxidative and ER stress in adipose tissue.Support or Funding InformationThe present study was carried out with the financial support of Department of Biotechnology (DBT), Ministry of Science and Technology, Government of India, and Indian Council of Medical Research (ICMR), Government of India. AS was supported by Council of Scientific and Industrial Research (CSIR).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.