Vitamin A deficiency increases hepcidin expression and oxidative stress in rat

The interaction between vitamin A and iron status has been widely reported; however, the exact mechanism involved in this interaction has not been well characterized. The present study investigated the mechanism involved in tissue iron accumulation and changes in the oxidative status in vitamin A-deficient rats.

Rats were treated with a control diet, a vitamin A-deficient diet, or a vitamin A/iron-deficient diet for 57 d. The animals were sacrificed; the blood, liver, and spleen were collected for biochemical analysis. Analysis of variance or Mann-Whitney tests were used to compare groups and Pearson's or Spearman's tests to investigate the bivariate correlation.

Vitamin A deficiency increased liver hepcidin mRNA and iron spleen concentrations; however, iron deficiency in vitamin A-deficient rats deeply inhibits liver hepcidin mRNA expression and significantly increases divalent metal transporter-1 mRNA levels. Liver ferroportin and hereditary hemochromatosis gene mRNA levels did not change in either treatment. In the vitamin A-deficient groups, liver carbonyl protein increased, whereas catalase and glutathione S-transferase activities decreased, suggesting that vitamin A protects the liver against protein oxidation. A significant positive correlation was found between lipid oxidative damage and iron concentration in the liver and spleen (r = 0.611, P = 0.007; r = 0.558, P = 0.025, respectively).

These results suggest that vitamin A maintains iron homeostasis by the modulation of liver hepcidin expression. The increase of lipid peroxidation in vitamin A deficiency seems to be iron dependent, whereas protein oxidation is not.