Hypercholesterolemia is one of the major risk factors that precipitate coronary heart disease and atherosclerosis. abnormal lipid metabolism is a main cause of dyslipidemia, which is a major risk factor for cardiovascular disease, obesity, cholestasis, and overall mortality. It is well known that diet plays an important role in the control of cholesterol homeostasis . Many studies reported that flaxseed may have protective effect against diseases like cardiovascular diseases CVD, reducing the risk of cancers, reducing the incident and progress of diabetes .High omega-6/omega-3 ratio intake promotes development of many chronic diseases like cardiovascular disease, cancer, inflammatory and autoimoune disease, rheumatoid arthritis, asthma. Accordingly, the purpose of the present study was to investigate the effect of flaxseed and flaxseed  oil against high cholesterol diet induced hypercholesterolemia in rats by adjusting ω6 :ω3ratio(2.5:1),. Also, to determine whether flaxseed  or flaxseed  oil when administered to hypercholesterolemic induced-rats beneficial for  treatment of hypercholesterolemia complications. Animals(40 rats) were divided randomly into 4 equal groups . G1 fed on basal diet (NC) , G2 fed on HFD only(PC) . G3 and G4 fed on HFD with adjust ω6 :ω3 ratio(2.5:1)  by either flaxseed oil (FSO) or flaxseed( FS) . Blood samples were collected every 3 weeks for lipid parameters monitoring (serum total cholesterol (TC) ,triglycerides (TG) .high  density lipoprotein cholesterol (HDL) whereas  low  density lipoprotein cholesterol (LDL) was calculated . All samples (heart, kidney, spleen, lungs and brain, and liver) of each animal were weighted. liver and kidney were kept in formalin solution (10%) for the histopathological investigation
Results showed that ω6 :ω3 ratio was 1:3.8 in FS and 1:4.2 in FSO , while such ratio was 10:1 in grease .
The results showed that adjusting ω6 :ω3 ratio by FS or FSO led to significant high decrease of plasma cholesterol, triglyceride, LDL and to increase in HDL after 6 weeks . Results also indicated that the balance ratio of ω6 :ω3 led to decrease in weight of rats as such ratio is important for health and in the prevention and management of obesity. Histopathology examination of the organs tissue was in parallel with the biochemical results, as liver weight was higher in PC with a marked deterioration in liver tissue while treated groups showed alleviated histopathological alterations. Moreover , kidney tissues in treated group showed apparently normal glomeruli and tubular epithelium, similar to the negative control group. These results suggest that, flaxseed oil may be effective in controlling cholesterolemic status and improving dyslipidemia and has the potential in reducing cardiovascular complications due to hypercholesterolemia.
Key words: Omega6, Omega3, lipid profile, Liver, Hypercholesterolemia ,high cholesterol diet , rats weight , Flaxseed oil; , Flaxseed