We investigated, by measuring
oxygen radical absorbance capacity (ORAC), whether
hyperoxia causes alterations in
antioxidant status and whether these alterations could be modulated by dietary
antioxidants. Rats were fed for 8 wk a control diet or a control diet supplemented with
vitamin E (500 IU/kg) or with aqueous extracts (ORAC: 1.36 mmol
Trolox equivalents/kg) from blueberries or spinach and then were exposed to air or >99% O2 for 48 h. Although the constituents of the extracts were not extensively characterized, HPLC indicated that
blueberry extract was particularly rich in
anthocyanins, and the spinach extract did not contain any
anthocyanins. The ORAC was determined in samples without
proteins [serum treated with
perchloric acid (PCA); ORACPCA] and with
proteins (ORACtot).
Hyperoxia induced a decrease in
serum protein concentration, an increase in serum ORACPCA, decreases in lung ORACPCA and ORACtot, and an equilibration of
proteins and ORACPCA between serum and
pleural effusion. These alterations suggested a redistribution of
antioxidants between tissues and an increase in capillary permeability during
hyperoxia. Only the
blueberry extract was effective in alleviating the
hyperoxia-induced redistribution of
antioxidants between tissues.