Effect of palm oil on oxidative stress-induced hypertension in Sprague-Dawley rats.
BACKGROUND
Oxidative stress, associated with increased plasma isoprostane (ISO) and reductions in plasma glutathione (GSH), has been shown to cause severe hypertension in normal rats. Palm oil (PO), with an unsaturated-to-saturated fatty acid ratio close to one and rich in antioxidant vitamins, has been investigated for its beneficial effects on arterial thrombosis and atherosclerosis. In this study, the effect of PO on oxidative stress induced by inhibition of GSH synthesis (using buthionine sulfoximine [BSO]) was examined.


METHODS
Sprague-Dawley rats were separated into two groups and received either natural vitamin-rich PO (Carotino, 5 g/kg daily) or water by gavage. After 4 weeks, they were further divided between receiving either BSO (30 mmol/L/day in the drinking water) or drug-free water for an additional week. Mean arterial pressure (MAP), heart rate (HR), and body weight (BW) were measured before and weekly during the experiment. The levels of plasma ISO, nitric oxide (NO), prostacyclin (PGI2), and thromboxane A2 (TXA2) were determined by enzyme immunoassay, and plasma, heart, and kidney GSH by high-performance liquid chromatography.


RESULTS
The PO reduced the age-dependent increase in MAP, and the pressor response to BSO, without changing the HR or BW compared to the BSO and control groups. It also elevated PGI2, NO, and aortic cGMP, but decreased TXA2 and aortic cAMP. In addition, the BSO-induced increase in ISO and TXA2, and the reduction in kidney GSH were attenuated by PO. However, the PO effect on NO, PGI2, cGMP, and TXA2 was partly counteracted by BSO.


CONCLUSIONS
Palm oil reduces BSO-induced oxidative stress and attenuates hypertension by mechanisms involving changes in endothelium-derived factors.
Ganafa
Agaba A
AA
Department of Pharmacology & Toxicology, Morehouse School of Medicine, Atlanta, Georgia 30310-1495, USA.
Socci
Robin R
RR
Eatman
Danita
D
Silvestrov
Natalia
N
Abukhalaf
Imad K
IK
Bayorh
Mohamed A
MA
D000818:Animals; D019328:Buthionine Sulfoximine; D003196:Computer Graphics; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000187:drug effects; D004791:Enzyme Inhibitors; D011464:Epoprostenol / Q000097:blood; D005978:Glutathione / Q000032:analysis; D006973:Hypertension / Q000097:blood / Q000139:chemically induced / Q000188:drug therapy*; D007124:Immunoenzyme Techniques; D028421:Isoprostanes / Q000097:blood; D009569:Nitric Oxide / Q000097:blood; D018384:Oxidative Stress / Q000187:drug effects*; D000073878:Palm Oil; D010938:Plant Oils / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013928:Thromboxane A2 / Q000097:blood
D004791:Enzyme Inhibitors; D028421:Isoprostanes; D010938:Plant Oils; D009569:Nitric Oxide; D019328:Buthionine Sulfoximine; D013928:Thromboxane A2; D000073878:Palm Oil; D011464:Epoprostenol; D005978:Glutathione