IJCS | Volume 31, Nº2, March / April 2018

120 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 TNF-α – segment 4 Control Cholesterol Group Flaxseed Median 25%-75% Min-Max Figure 2 – Mean tumor necrosis factor alpha (TNF- α ) values at the animals’ aortic segment 4 in each group. Martins et al. Flaxseed ReducesTNF-α Int J Cardiovasc Sci. 2018;31(2)114-122 Original Article effective in decreasing TG levels. This result is in line with those from previous studies and suggests that dietary supplementation with omega-3 via the consumption of flaxseed helps decrease TG levels, possibly via the decrease of remaining chylomicron particles and the inhibition of the synthesis and secretion of very low‑density lipoprotein (VLDL-C) by the liver. 22 Cintra et al. 23 tested the effect of the consumption of a high-fat flaxseed-based diet in Wistar rats and observed a reduction in TC and TG levels, higher fecal excretion of lipids, and lower deposition of cholesterol in the liver. This result was similar to that obtained by Bhathena (2003). 23 Immunohistochemistry was used to investigate the presenceoftwomarkersinvolvedininflammation,acellular adhesion molecule (ICAM-1) and a proinflammatory cytokine (TNF- α ). Several studies have used ICAM-1 as a marker of inflammation. In a study with 60 rabbits (10 in the control group and 50 in the atherosclerotic group), animals fed a high-fat diet exhibited higher levels of ICAM-1 in the aorta comparedwith those in the control group (p < 0.01), which indicates a role for ICAM-1 as a predictor of cardiovascular disease. 25 The importance of the present study lies in the analysis of ICAM-1 in four aortic segments. The results indicated an increase in ICAM-1 levels in all animal groups and all tissue sections; however, the results were not statistically significant. A similar result was obtained in an animal study conducted by Prim et al., 8 and in human studies, which also showed nonsignificant reductions in the levels of ICAM-1 and VCAM-1 markers. 26 We should emphasize that no antiinflammatory activity was observed in the group that received flaxseed (G3), suggesting that the findings of the antiinflammatory effect of omega-3 fatty acids are contradictory. In addition, the results of ICAM-1 suggest that this activity is dependent on the duration of consumption of omega-3 fatty acids. The results of the TNF- α analysis indicated a significant difference among the groups. TNF- α levels were higher in G1 than G3. This result demonstrated an effect of flaxseed, but was not statistically significant. Moreover, the levels of TNF- α increased in G2, which indicates that this marker is associated with stress and inflammation. A similar result was observed in a previous study, 27 in which the elevated levels of TNF- α were associated with recurrent coronary events after myocardial infarction. Levels of the inflammatory marker TNF- α decreased significantly in group G3 (flaxseed group), which favors the hypothesis that flaxseed components can reduce antiinflammatory and antiatherogenic activity. Aprevious study has observed a decrease in TNF- α levels after the consumption of omega-3 fatty acids by most patients. 28