Protective effect of ascorbic acid on cadmium-induced hypertension and vascular dysfunction in mice

Cadmium (Cd) is one of the most important environmental pollutants that cause a number of adverse health effects in humans and animals. Recent studies have shown that Cd-induced oxidative damage within the vascular tissues results in vascular dysfunction. The current study was aimed to investigate whether ascorbic acid could protect against Cd-induced vascular dysfunction in mice. Male ICR mice were received CdCl₂ (100 mg/l) via drinking water for 8 weeks alone or received ascorbic acid supplementation at doses of 50 and 100 mg/kg/day for every other day. Results showed that Cd administration increased arterial blood pressure and blunted the vascular responses to vasoactive agents. These alterations were related to increased superoxide production in thoracic aorta, increased urinary nitrate/nitrite, increased plasma protein carbonyl, elevated malondialdehyde (MDA) concentrations in plasma and tissues, decreased blood glutathione (GSH), and increased Cd contents in blood and tissues. Ascorbic acid dose-dependently normalized the blood pressure, improved vascular reactivities to acetylcholine (ACh), phenylephrine (Phe) and sodium nitroprusside (SNP). These improvements were associated with significant suppression of oxidant formation, prevention of GSH depletion, and partial reduction of Cd contents in blood and tissues. The findings in this study provide the first evidence in pharmacological effects of ascorbic acid on alleviation of oxidative damage and improvement of vascular function in a mouse model of Cd-induced hypertension and vascular dysfunction. Moreover, our study suggests that dietary supplementation of ascorbic acid may provide beneficial effects by reversing the oxidative stress and vascular dysfunction in Cd-induced toxicity.