Comparative Effects of Two Edible Vegetable Oils in South East Nigeria on Dexamethasone Induced Dyslipidaemic Albino Wistar Rats

Dyslipidaemia is a risk factor for cardiovascular diseases. A lipid profile of an organism is a direct measure of three blood components namely; total cholesterol (TC), triglycerides and high density lipoproteins cholesterol (HDL-C). Hypercholesterolemia is a lipoprotein metabolic disorder characterized by high serum low density lipoprotein and blood cholesterol and one of the most important risk factors for the development of cardiovascular diseases and lipid abnormalities. There have been many claims that most, if not all brands of vegetable oil in Nigeria is cholesterol free. Hence the study was undertaken to see the effect of vegetable oils in Nigeria on the lipid profile of albino rats induced with dyslipidaemia using dexamethasone. The phytochemical analysis and lipid profiles of albino rats treated with two vegetable oils were undertaken. Five groups of five rats were used in the study as follows: Group 1: Normal control- no induction no treatment, Group 2: Induction of dyslipidemia using dexamethasone (1 mg/kg bw) for 5 days only, Group 3: Treatment of induced dyslipidemia using a standard statin (20 mg/kg bw), Group 4: Induction + 3 ml/kg bw vegetable oil after induction, Group 5: Treatment without dyslipidemia using vegetable oil (3 ml/kg bw). The treatment lasted for 14 days and thereafter, the rats were fasted overnight and blood samples were taken through ocular puncture. The results showed various phytochemicals such as terpenoids, steroids, flavonoids, phenolics, tannins and alkaloids. The lipid profiles of the albino rats revealed that a non-significant (P>0.05) increase was observed in serum total cholesterol level of groups 3 and 5 when compared to group 2 while group 4 recorded a non-significant (P>0.05) decrease when compared to group 2. There was a non-significant (P>0.05) increase in serum triacylglycerol level of groups 3, 4, and 5 when compared to group 2. The result also showed a non-significant (P>0.05) decrease in serum HDL level in groups 3, 4, and 5 compared to group 2. Also, group 3 indicated a significant (P<0.05) increase in serum LDL level compared to group 2 while group 4 recorded a non-significant (P>0.05) decrease in serum LDL level compared to group 2. However, a significant (P<0.05) increase in serum LDL level was recorded in group 5 compared to group 2. The second vegetable oil revealed that group 3 indicated a non-significant (p>0.05) increase in total cholesterol level while groups 4 and 5 recorded a significant (p<0.05) decrease compared to group 2. Groups 3, 4 and 5 recorded a non-significant (p>0.05) increase in TAG compared to group 2. Group 3 recorded a significant (p<0.05) increase in LDL compared to group 2. Group 4 recorded a non-significant (p>0.05) decrease while group 5 recorded a significant (p<0.05) decrease in LDL compared to group 2. Groups 3, and 5 recorded a non-significant (p>0.05) decrease in HDL compared to group 2. Group 4 showed a significant (P<0.05) decrease in HDL compared to group 2. However, among the oil treated groups, TAG was found to be within range compared to the control group. Thus, the results of this present study imply that the consumption of vegetable oil for a long time could influence the risk of cardiovascular disease since they elicited an elevation of LDL-cholesterol and lowered HDL-cholesterol. Caution should, therefore, be applied on the consumption of vegetable oils as continuous use may have impact on lipid profile thereby causing dyslipidaemia.