The present work was conducted to study the cardioprotective
effects of long term administration of two antihypertensive drugs
namely valsartan, a specific AT 1 blocker, and lacidipine, a
dihydropyridine calcium antagonist, in male rabbits fed high
cholesterol diet for two months. Their actions on the serum creatine
phosphokinase (CPK), lipid profile, total cholesterol (T.ch),
triglycerides (T.G), low density lipoprotein (LDL), high density
lipoprotein (HDL) and their actions on aorta and the infarct size of
atherosclerotic rabbits were investigated.
Male rabbits were rendered atherosclorotic by feeding
cholesterol in a daily dose of 100 mg / kg for 2 months. Over the
same period of cholesterol feeding, rabbits were treated with either
valsartan (20 mg/kg orally) or lacidipine (3 mg / kg / day orally). At
the end of the two months, rabbits were subjected to coronary artery
ligation (LAD) for 4 hours. Three parameters were studied namely
electrophysiological parameter recording S-T segment elevation
using electrocardiogram, biochemical parameter recording plasma
CPK before and after 4 hours of ligation of LAD and histochemical
parameter (staining heart sections with triphenyl tetrazolium (TPT)
4 hours after ligation of LAD and the infarct areas were computed,
in addition histopathological changes in aorta were studied.
In this study both valsartan and lacidipine decreased
significantly S-T segment elevation after LAD ligation compared to
the atherosclerotic group. Also both drugs significantly decreased
the rise in CPK level 4 hours after ligation of LAD compared to the
atherosclerotic group at the same time interval. Both of them
decreased the infarct size significantly compared to the
atherosclerotic group. Moreover lacidipine, but not valsartan
improved lipid profile of atherosclerotic animals, but both drugs
improved histopathological changes in aorta.
From all the results of this study it can be concluded that both
valsartan and lacidipine can be used in acute myocardial infarction
to limit the infarct size. Long term adminstration of both drugs is
effective and of great value in decreasing the incidence of
myocardial infraction or decreasing its size. Since both drugs
inhibited development of atherosclerosis on long-term
administration which is a major risk factor in development of
coronary heart disease, so both drugs are efficient prophylactic
agents in patients liable to atherosclerosis and coronary heart
diseases.
|
