TY - JOUR
T1 - Long-term ingestion of Hibiscus sabdariffa calyx extract enhances myocardial capillarization in the spontaneously hypertensive rat
AU - Inuwa, Ibrahim
AU - Ali, Badreldin H.
AU - Al-Lawati, Intisar
AU - Beegam, Sumaya
AU - Ziada, Amal
AU - Blunden, Gerald
N1 - Funding Information:
This work was supported by an internal grant from Sultan Qaboos University (SQU). We thank the staff of the Animal House of SQU for looking after the rats.
PY - 2012/5
Y1 - 2012/5
N2 - The effects of Hibiscus sabdariffa (HS) in lowering blood pressure in human and animal hypertension have been documented. This study investigated the effect of the water extract of the dried calyx of HS and Hibiscus anthocyanins (HAs) on left ventricular myocardial capillary length and surface area in spontaneously hypertensive rats (SHRs). Twelve-week-old male SHRs were divided into eight groups (six rats in each group). Three groups were given three doses; 10%, 15% and 20% of the water extract of HS in lieu of drinking water for 10 consecutive weeks (HS10, HS15 and HS20) with one group kept as control (C). Another three groups were given three doses of the HAs orally at doses of 50, 100 and 200 mg/kg for five consecutive days with one group kept as a control (C). Systolic (SBP) and diastolic (DBP) blood pressures, as well as heart rate (HR), were measured weekly. After the experimental protocols, the left ventricles (LV) of all rats were obtained. Capillary surface area density and length density were determined by unbiased sterological methods on 3 mm LV tissue samples from perfusion-fixed hearts. HS ingestion significantly reduced SBP, DBP and LV mass in a dose-dependent fashion but did not affect the HR. HS significantly increased surface area and length density of myocardial capillaries by 59%, 65% and 86%, and length density by 57%, 77% and 57%, respectively. Myocyte nuclear volume was significantly decreased in HS-treated rats. There was a decrease (although insignificant) in SBP and DBP with HA ingestion compared with controls. These changes suggest that the observed beneficial effect of HS on high BP in SHRs could be mediated through a reduction in the diffusion distance between capillaries and myocytes, as well as new vessel formation. It is proposed that these effects might be beneficial in restoring myocyte normal nutritional status compromised by the hypertrophic state of hypertension.
AB - The effects of Hibiscus sabdariffa (HS) in lowering blood pressure in human and animal hypertension have been documented. This study investigated the effect of the water extract of the dried calyx of HS and Hibiscus anthocyanins (HAs) on left ventricular myocardial capillary length and surface area in spontaneously hypertensive rats (SHRs). Twelve-week-old male SHRs were divided into eight groups (six rats in each group). Three groups were given three doses; 10%, 15% and 20% of the water extract of HS in lieu of drinking water for 10 consecutive weeks (HS10, HS15 and HS20) with one group kept as control (C). Another three groups were given three doses of the HAs orally at doses of 50, 100 and 200 mg/kg for five consecutive days with one group kept as a control (C). Systolic (SBP) and diastolic (DBP) blood pressures, as well as heart rate (HR), were measured weekly. After the experimental protocols, the left ventricles (LV) of all rats were obtained. Capillary surface area density and length density were determined by unbiased sterological methods on 3 mm LV tissue samples from perfusion-fixed hearts. HS ingestion significantly reduced SBP, DBP and LV mass in a dose-dependent fashion but did not affect the HR. HS significantly increased surface area and length density of myocardial capillaries by 59%, 65% and 86%, and length density by 57%, 77% and 57%, respectively. Myocyte nuclear volume was significantly decreased in HS-treated rats. There was a decrease (although insignificant) in SBP and DBP with HA ingestion compared with controls. These changes suggest that the observed beneficial effect of HS on high BP in SHRs could be mediated through a reduction in the diffusion distance between capillaries and myocytes, as well as new vessel formation. It is proposed that these effects might be beneficial in restoring myocyte normal nutritional status compromised by the hypertrophic state of hypertension.
KW - Anthocyanins
KW - Blood pressure
KW - Heart
KW - Hibiscus sabdariffa
KW - Rats
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U2 - 10.1258/ebm.2012.011357
DO - 10.1258/ebm.2012.011357
M3 - Article
C2 - 22678012
AN - SCOPUS:84862010432
SN - 1535-3702
VL - 237
SP - 563
EP - 569
JO - Experimental Biology and Medicine
JF - Experimental Biology and Medicine
IS - 5
ER -