Effect of flaxseed supplementation and exercise training on lipid profile oxidative stress and inflammation in rats with myocardial ischemia.

January 1, 2012 Human Health and Nutrition Data 0 Comments

Effect of flaxseed supplementation and exercise training on lipid profile oxidative stress and inflammation in rats with myocardial ischemia.

Year: 2012
Authors: Nounou, H.A. Deif, M.M.Shalaby, M.A.
Publication Name: Lipids in Health & Dis.
Publication Details: Volume 11; Page 129


Flaxseed has recently gained attention in the area of cardiovascular disease primarily because of  its rich contents of α-linolenic acid (ALA), lignans, and fiber. Although the benefits of exercise on any single risk factor are unquestionable, the effect of exercise on overall cardiovascular risk, when combined with other lifestyle modifications such as proper nutrition, can be dramatic. This study was carried out to evaluate the protective role of flaxseed and exercise on cardiac markers, lipids profile and inflammatory markers in isoproterenol (ISO) induced myocardial ischemia in rats. The research was conducted on 40 male albino rats, divided into 4 groups (n of 10): group I served as control, group II has acute myocardial ischemia induced by isoproterenol, groups III and IV have acute myocardial ischemia induced by isoproterenol pretreated with flaxseed supplementation orally for 6 weeks, additionally group IV practiced muscular exercise through swimming. Alterations of lipid profile, cardiac and inflammatory markers (Il 1 beta, PTX 3 and TNF alpha) were observed in myocardial ischemia group. Flaxseed supplementation combined with exercise training showed significant increase of HDL and PON 1, on the other hand cardiac troponin, Il- 1beta and TNF alpha levels significantly decreased as compared to myocardial ischemic group. Receiver Operating Characteristics (ROC) analysis of cTnI, PTX 3, Il 1beta and TNF alpha revealed a satisfactory level of sensitivity and specificity. Regular exercise enhances the improvement in plasma lipoprotein levels and cardiovascular protection that results from flaxseed supplementation by mitigating the pathophysiology of atherosclerosis. Elevation of HDL, the antioxidant PON 1 and the cardioprotective marker PTX 3 emphasizes the protective effects of flaxseed and muscular exercise mutually against the harmful effects of acute myocardial ischemia. (Authors abstract)
Reduction of heart oxygen supply due to coronary obstruction leads to diminution of oxygen supply to the mitochondria to support oxidative phosphorylation and eventually ischemia. The effects of flaxseed supplementation on plasma lipids have remained controversial. Cardiac troponin (cTnI) has been established as one of the most useful biomarkers for risk assessment and management of suspected acute coronary syndrome patients. Previous studies reported that elevated cTnI levels are highly specific for cardiac injuries.  To gain insight about the cardiovascular effects of flaxseed and to understand its mechanisms, this study examined the prophylactic role of flaxseed supplementation alone and in combination with exercise in isoproterenol induced myocardial ischemia in rats. A remarkable elevation of cholesterol level to 69.6 plus or minus 9.2 mg/dl with increase up to 249.5 percent relative to control (P less than 0.0001) was determined and attributed to myocardial ischemia in group II. Flaxseed supplementation in group III dropped cholesterol level to nearly the control level 28.8 plus or minus 2.8 mg/dl with mild increase of 103 percent compared to control. Cholesterol level decreased significantly due to exercise training combined with flaxseed in group IV to 26.4plus or minus1.0 mg/dl compared to myocardial ischemia group (P less than 0.0001) with decrease down to 94.6 percent relative to control (Table 1 and Figure 1).
The myocardial ischemia group II had LDL level of 33.9 plus or minus 2.8 mg/dl, significantly higher than group III (flaxseed supplemented group and group) IV (flaxseed supplemented group combined with exercise training) (P less than 0.0001). Flaxseed supplementation in group III decreased LDL to 26.3 plus or minus 3.0 mg/dl with decrease down to 63.4 percent to control, while exercise training combined with flaxseed supplementation decreased LDL to 24.5 plus or minus1.8mg/dl with 59 percent in group IV as compared to the control. There was a significant increase of high density lipoprotein (HDL) to 34.3 plus or minus 1.9 mg/dl in group IV which was on flaxseed supplementation and exercise training as compared with the other groups (P less than 0.0001), with increase up to 129.4 percent increase as compared to the control. While the marker of ischemic myocardial injury cTnI was increased due to myocardial ischemia in group II as compared to the control, flaxseed supplementation in group III ameliorated the level of cTnI to 0.2 plus or minus 0.02 ng/ml (P less than  0.0001) almost 100 percent as the control. The antiatherogenic potential benefits of flaxseed, that has been received in both group III and IV, protected against the loss of endothelial-dependent vascular relaxation in cholesterol fed animals. A significant decrease in plasma IL 1 beta levels in group III which received flaxseed supplementation to 35.1 plus or minus 4.8 pg/ml as compared with the myocardial ischemia group II (P less than 0.0001) with decrease down to 58.5 percent relative to the control was noted. There was diminution in plasma TNF alpha of 90.7 percent in group III as compared to the control group, this is in accordance with previous data demonstrating that flaxseed consumption inhibits TNF alpha synthesis and reduces cytokine production by peripheral mononuclear cells. The results showed alterations in the lipid profiles of isoproterenol-treated rats (group II); with increase of total cholesterol and triglycerides, the marker of ischemic myocardial injury, cTnI also increased in the same group, all the inflammatory biomarkers IL-1beta, PTX 3 and TNF- alpha level increased with myocardial ischemia. This study highlights that combination of flaxseed and exercise is one of the promising cytoprotective elements for improving defense mechanisms in the physiological systems against oxidative stress and inflammation caused by myocardial ischemia. (Editors comments)

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