STUDY ON PROTECTION OF CARDIOVASCULAR SYSTEM AND KIDNEY BY DIFFERENT ANGIOTENSIN RECEPTOR BLOCKERS IN EXPERIMENTALLY INDUCED HYPERTENSIVE ADULT MALE ALBINO RATS

Abstract

Background: In treatment of hypertension, care should be taken for
preventing hypertensive organ injuries as well as lowering blood pressure
to the adequate level in order to decrease the risk of cardiovascular and
renal diseases. Objectives: To assess and compare the possible protective
effect of various angiotensin receptor blockers namely candesartan,
olmesartan, telmisartan ,and valsaratn on cardiovascular and renal tissues in
renal hypertensive rats Methods: In this study 72 adult male albino rats
were used and divided into six equal groups (each of 12 rats): Group 1,
control normal received the vehicle; Group 2, control renal hypertensive
induced by left renal artery ligation received the vehicle and Group 3
treated renal hypertensive rats which is divided into four subgroups:
subgroup (A) received candesartan ( 0.1 mg/kg/day); subgroup (B) received
olmesartan ( 3mg/kg/day ); subgroup (C) received telmisartan ( 0.5
mg/kg/day),and subgroup (D) received valsartan (0.5 mg/kg/day). Rats
received drugs orally by gavage once daily for 2 weeks. Results: The
present study revealed that left renal artery ligation induced significant
increases in mean arterial blood pressure (MABP), heart rate (HR), heart
weight, cardiac fibrosis and glomerulosclerosis. Also, there were significant
increases in serum level of tumor necrosis factor alpha (TNF-α), cardiac
level of inteleukin1β (IL1β), and cardiac and renal levels of
malondialdehyde (MDA) concomitant with significant reduction in cardiac
and renal level of reduced glutathione (GSH). MABP was similarly reduced
in candesartan, olmesartan, telmisartan and valsartan groups compared to
control renal hypertensive group. Heart rate, cardiac weight, and cardiac
fibrosis were significantly reduced in telmisartan and candesartan group.
Telmisartan and candesartan suppressed serum level of TNFα and the
cardiac level of IL-1β. Meanwhile, olmesartan and valsartan significantly
decreased glomerulosclerosis index and renal level of MDA with
significant increase in renal level of GSH. Conclusion: Telmisartan and
candesartan exerted better cardioprotective effect via prevention of
inflammatory cascade, and olmesartan and valsartan exerted better
renoprotective effect via enhancement of antioxidant capacity.
Key words: hypertension, angiotensin receptor blockers, candesartan,
olmesartan, telmisartan, valsartan, TNF-α, IL1β, MDA and GSH.