EFFECTS OF ALLIUM SATIVUM EXTRACT TREATMENT ON CARDIAC AND RENAL REGULATION OF BLOOD PRESSURE IN HYPERTENSION-INDUCED LABORATORY RATS (Rattus norvigecus)

Abstract

Hypertension is a major cause of morbidity and mortality due to its association with coronary heart disease, cerebrovascular disease and renal disease. Fresh Allium sativum bulbs have been alleged to have blood pressure lowering effects. However, the exact mechanism and long-term effects are not fully been understood. The aim of this study was to investigate the effects A. sativum extract treatment on cardiac and renal regulation of blood pressure in hypertension-induced male DOCA-salt model wistar laboratory rats. Sixty four male DOCA-salt wistar rats weighing 250-300g, 36 weeks old were induced to hypertension and studied for 20 weeks. Doses of 50, 100 and 200 mg/kg body weight of A. sativum were prepared (FAGE-T1, CGE-T2 and CIGE-T3) and administered intraperitonially (IP) twice a day. Plasma levels of electrolytes (Na+, K+, Ca2+, Cl-), enzymes, heart histology and electrocardiogram recording were analysed. From the study, A. sativum extracts did not have effect on the mean plasma antidiuretic hormone (ADH) in comparison to the normotensive control group at p<0.05. However, FAGE 200mg/Kg body weight significantly decreased plasma B-type atrial natriuretic peptide (ANP) by 29.5% (n = 4; p<0.05) compared to the control group treated with normal saline (NS). The antihypertensive drugs Captoten (CPT) and Hydrochlorothiazide (HCT) lowered the mean plasma angiotensin II (Ang-II) levels by 30% (n = 4; p<0.05) and by 36.75% (n = 4; p<.05) of the control. No effect was noted in control groups C1, C2 and group T1 on mean plasma levels of aldosterone hormone (Ald). However, A. sativum extracts (CGE and CIGE) significantly lowered the mean plasma levels of Ald after longer treatment (20 weeks), compared to the control group (n = 4; p<0.05) by 7.67% (n =4; p<0.05) and 17% (n = 4; p<0.05) respectively. A. sativum extracts decreased mean plasma renin levels just as the antihypertensive drugs used in treatment groups C2 and C3 respectively, compared to the control group (n = 4; p<0.05). All A. sativum extracts showed significant decrease in mean plasma Na+ ion (p<0.05) at all concentration levels in all hypertensive groups by 15.625% (n = 4; p<0.05) compared to the control group (n = 4; p<0.05). Seven out of 11 treatments significantly lowered mean plasma K+ ion levels (n =4; p<0.05 = 79.72%). All A. sativum extracts triggered significant decrease in mean plasma levels of Chloride (Cl-) ions (n = 4; p<0.05 = 23.25%). A. sativum extract concentrations did not show statistically significant change in mean plasma ionic Calcium (iCa2+) levels compared to the control group (p<0.05). A. sativum extracts did not have significant effect on metabolites across all the treatment groups. A. sativum extract concentrations significantly reduced systolic blood pressure (SBP) from 150mmHg to 110mmHg (36.36% reduction) as compared to SBP in the normotensive control group at p<0.05 when used longer (20 weeks). All A. sativum extracts recorded significant decrease in mean diastolic blood pressure (DBP) with the least mean diastolic blood pressure of 63mmHg in the hypertensive treatment groups C2b, C3b and T1b (10.7% decrement) compared to the normotensive control group with 56.91mmHg at p<0.05 treated with NS. Electrocardiogram (ECG) recordings showed that A. sativum extracts reduced the RR intervals, QT intervals and Heart rate. Histological findings showed that FAGE had reversal effects on the myocardium post-hypertension as compared to the control, groups T2 and T3. These findings signify that garlic (A. sativum) use modulatory mechanisms including reduction of sodium ion concentration, reduction of systolic and diastolic blood pressure, plasma cholesterol levels, and renin.