Lead (Pb) and
cadmium (Cd) are
environmental pollutants and nonessential elements in the body. Both metals induce the development of
hypertension which is associated with oxidative stress.
Curcumin (CUR) is a polyphenolic compound with strong
antioxidant activity. The present study evaluated the effect of CUR on oxidative stress, alteration of vascular responsiveness and
hypertension induced by exposure to either Pb, Cd or the combination of Pb and Cd. Male Sprague-Dawley rats were exposed to low level of
lead acetate (100 mg/L) and/or
cadmium chloride (10 mg/L) in the
drinking water for 16 weeks. The control animals received deionized water as
drinking water. CUR (100 mg/kg) or
propylene glycol as vehicle was intragastrically administered once daily for the last 4 weeks. Exposure to Pb, Cd or the combination induced increases in blood pressure and peripheral vascular resistance, and decreased the blood pressure response to
intravenous infusion to
acetylcholine. Supplementation with CUR significantly reduced blood pressure, alleviated oxidative stress, and increased plasma
nitrate/
nitrite and
glutathione in the blood. The effects of CUR were associated with the improvement of vascular responsiveness, upregulation of the
endothelial nitric oxide synthase and downregulation of the
NADPH oxidase expression. Furthermore, CUR reduced the
metal levels in blood, aorta, liver and kidney. Altogether, exposure to the combination of Pb and Cd aggravated
hypertension and oxidative stress, and CUR effectively ameliorated these adverse events in
metal exposed animals. Data indicate that CUR may be useful as a dietary supplement for protection against the noxious effects of the
heavy metals.