The aim of the present study was to evaluate the effect of diets rich in n-6 and n-3 fatty acids on adipose tissue metabolism. Starting at weaning, male Wistar rats were fed ad libitum, for 8 weeks with one of the following diets: C, rat chow; S, rat chow containing 15 % (w/w) soyabean oil; F, rat chow containing 15 % (w/w) fish oil; SF, rat chow containing 15 % (w/w) soyabean and fish oil (5:1, w/w). Casein was added to the fat diets to achieve the same 20 % (w/w) protein content as in the control chow. Food intake and body weight were measured weekly. The rats were killed by decapitation and the retroperitoneal (RET) and epididymal (EPI) white adipose tissues were removed and weighed. Tissue lipid and protein content, in vivo lipogenesis rate, uptake of diet-derived lipids, in vitro lipolytic rate, adipocyte area, lipoprotein lipase, ATP citrate lyase, and malic enzyme activities were evaluated. Carcass lipid and protein contents were also measured. Energy intake was reduced while carcass lipid content was increased in the three fat-fed groups. However, carcass protein and body weight gains were elevated only with diets F and SF. Lipolysis rate was diminished by diets F and SF, while the uptake of diet-derived lipids was elevated by the diet S in both RET and EPI tissues. These metabolic alterations may have contributed to the increase in in vivo lipogenesis rate in the presence of decreased ATP citrate lyase and malic enzyme activities induced by the three lipid diets. These results indicate that enrichment of the diet with polyunsaturated fatty acids causes changes in adipose tissue metabolism that favour fat deposition. Different metabolic pathways were preferentially affected by each type of fatty acid used.

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Polyunsaturated fatty acid-rich diets: effect on adipose tissue metabolism in rats

Diets rich in polyunsaturated fatty acids: effect on hepatic metabolism in rats.

BACKGROUND AND PURPOSE The serine and cysteine peptidase inhibitor, BbCI, isolated from Bauhinia bauhinioides seeds, is similar to the classical plant Kunitz inhibitor, STI, but lacks disulphide bridges and methionine residues. BbCI blocks activity of the serine peptidases, elastase (Kiapp 5.3 nM) and cathepsin G (Kiapp 160.0 nM), and the cysteine peptidase cathepsin L (Kiapp 0.2 nM). These three peptidases play important roles in the inflammatory process.



EXPERIMENTAL APPROACH We measured the effects of BbCI on paw oedema and on leucocyte accumulation in pleurisy, both induced by carrageenan. Leucocyte–endothelial cell interactions in scrotal microvasculature in Wistar rats were investigated using intravital microscopy. Cytokine levels in pleural exudate and serum were measured by elisa.



KEY RESULTS Pretreatment of the animals with BbCI (2.5 mg·kg−1), 30 min before carrageenan-induced inflammation, effectively reduced paw oedema and bradykinin release, neutrophil migration into the pleural cavity. The number of rolling, adhered and migrated leucocytes at the spermatic fascia microcirculation following carrageenan injection into the scrotum were reduced by BbCI pretreatment. Furthermore, levels of the rat chemokine cytokine-induced neutrophil chemo-attractant-1 were significantly reduced in both pleural exudates and serum from animals pretreated with BbCI. Levels of interleukin-1β or tumour necrosis factor-α, however, did not change.



CONCLUSIONS AND IMPLICATIONS Taken together, our data suggest that the anti-inflammatory properties of BbCI may be useful in investigations of other pathological processes in which human neutrophil elastase, cathepsin G and cathepsin L play important roles.

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Effect of plant neutrophil elastase inhibitor on leucocyte migration, adhesion and cytokine release in inflammatory conditions

It was investigated whether dietary polyunsaturated fatty acids (PUFA) could influence colonic injury, tissue DNA damage, cytokines and myeloperoxidase activity (MPO) and plasma corticosterone in DSS-induced colitis rats. Male weaning Wistar rats were fed for 47 days with an AIN-93 diet with control (C), fish (F) or a mixture of fish and soybean oil (SF). The colitis was induced from day 36 until day 42 by 3% DSS in drinking water. On day 48, blood samples were collected for corticosterone determination. The distal colon was excised for histological analysis and to quantify the cytokine (IL-4, IL-10 and INF-γ), MPO and DNA damage. The disease activity index (DAI) was recorded daily during colitis induction. The DAI, MPO, histological analyses showed decreases only in the SF group compared with the C group. IL-10 was increased and DNA damage was reduced in the groups F and SF, and an inverse correlation between these variables was found. There were no differences in corticosterone, IFN-γ and IL-4 levels. Soybean and fish oil mixture may be effective in improving colonic injury and DNA damage, and it could be an important complementary therapy in UC to reduce the use of anti-inflammatory drugs and prevent colorectal cancer.

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Soybean and fish oil mixture increases IL-10, protects against DNA damage and decreases colonic inflammation in rats with dextran sulfate sodium (DSS) colitis

Background Cancer-related fatigue (CRF) is a common side effect of adjuvant therapy and becomes a chronic problem for approximately one-third of survivors. Omega-3 polyunsaturated fatty acids (O3-PUFA) demonstrated preliminary antifatigue effects in previous research, but have not been investigated in fatigued cancer survivors. Methods Breast cancer survivors 4-36 months posttreatment with a CRF score of 4 or more of 10 using the symptom inventory (SI) were randomly assigned to O3-PUFA (fish oil, 6 g/d), omega-6 PUFA (O6-PUFA; soybean oil, 6 g/d), or a low-dose combination of O3-/O6-PUFA (3 g/d O3-PUFA and O6-PUFA) for 6 weeks. CRF was assessed by the SI (screening question), the Brief Fatigue Inventory, and the Multidimensional Fatigue Symptom Index. Protein and mRNA levels of inflammatory and antioxidant biomarkers, along with fatty acid and lipid levels, were assessed at baseline and week 6. Statistical tests were two-sided. Results A total of 108 breast cancer survivors consented; 97 subjects were randomly assigned and 81 completed the trial. The SI CRF score decreased by 2.51 points at week 6 with O6-PUFA and by 0.93 points with O3-PUFA, with statistically significant between-group difference (effect size = -0.86, P < .01). Similar changes were observed for the Brief Fatigue Inventory and Multidimensional Fatigue Symptom Index but were not statistically significant. Stratified analyses showed the largest benefit was observed in those with severe baseline CRF (≥7). Compared with O3-PUFA, O6-PUFA supplementation statistically significantly decreased proinflammatory markers in the TNF-α signaling pathway. Conclusion Contrary to our original hypothesis, O6-PUFA statistically significantly reduced CRF compared with O3-PUFA. Further research is needed to confirm these findings and to elucidate mechanisms of action.

/pdf/multicenter-randomized-controlled-trial-of-omega-3-fatty-tn3gfgzcaz.pdf

Multicenter Randomized Controlled Trial of Omega-3 Fatty Acids Versus Omega-6 Fatty Acids for the Control of Cancer-Related Fatigue Among Breast Cancer Survivors.

The effect of an n-3 (fish) and n-6 (soybean) fatty acid-rich diet on carrageenin paw oedema in rats, and the participation of adrenal gland, corticosterone and α2-macroglobulin (α2-M) in this process were studied. A significant inhibition of carrageenin oedema was observed not only in rats fed a diet rich in fish oil but also in the soybean group. α2-M was not detectable before carrageenin injection, suggesting that this putative antiinflammatory factor does not participate in the observed anti-inflammatory effect. Corticosterone levels were higher in fat-fed than in control rats, before carrageenin stimulus and adrenalectomy abolished the anti-inflammatory response in fat-fed animals, showing the important role of the adrenocortical hormones in this process.

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E. A. Limãos

Papers

Participation of the adrenal gland in the anti-inflammatory effect of polyunsaturated diets.