The effect of different beta-adrenoceptor antagonists on atherosclerotic plaque in hypercholesterolemic rabbits

الملخص EN

Both hypertension and atherosclerosis are two major causes of morbidity and mortality in the society and several drugs used for the antihypertensive therapy may modify the lipids and lipoproteins metabolism and affect atherosclerosis rate.

_-adrenoceptor antagonists frequently used for the treatment of the cardiovascular disease such as hypertension, cardiac arrhythmia, and ischemic heart disease.

In this study we studied the effects of different_-adrenoceptor antagonists (carvedilol, atenolol and propranolol) on atherosclerotic plaque area and lipid profiles in hypercholesterolemic rabbit.

The hypercholesterolemia was induced in thirty two female rabbits by daily feeding of atherogenic diet (1 % cholesterol powder (wt / wt) + rabbit chow) for 10 weeks, animals were divided into 4 groups, each group contain 8 rabbits treated for 10 weeks with following : placebo, carvedilol 1mg / kg, atenolol 1mg / kg and propranolol 5mg / kg, given orally daily before feeding.

Both carvedilol and propranolol produced a statistically significant reduction in atherosclerotic plaque in the arch of aorta (P < 0.01), (P < 0.05) respectively, while atenolol has no statistical significant effect.

Carvedilol lowers serum cholesterol and low density lipoprotein levels at 5 weeks, while atenolol causes a significant decrease in cholesterol and low density lipoprotein levels (P < 0.05) at 10 weeks.

On the other hands propranolol causes a significant reduction in high density lipoprotein levels (P < 0.05) at 10 weeks, also significant increase in the triglyceride levels at 10 weeks (P < 0.05).

In conclusion, that _-adrenoceptor antagonists like carvedilol has the most favorable effect on both atherosclerosis and lipid profile, atenolol did not have a significant deleterious effect on atherosclerosis but had favorable effect on lipid profile, in contrast with propranolol which can reduce the size of atherosclerotic plaque despite its un favorable effect on lipid profile.