[Effect of beta-carotene supplementation on DNA oxidative and alkylation damage in rats]

To investigate the effect of beta-carotene (P-C) supplementation on DNA oxidative and alkylation damage in rats.

Rats were randomly divided into five groups. The first group was no beta-C, and the second, the third, the forth and the fifth groups were daily supplemented with 0.071, 0.355, 4.28 and 15.0 mg/(kg x d). The content of plasma VA was analyzed by fluorescent spectrometry. DNA damage and oxidative damage induced by H2O2 were detected by single-cell gel electrophoresis (SCGE) and O6-Methyl-guanine (O6-MeG) was measured by high performance capillary zone electrophoresis.

After 8 weeks trial, the results showed that levels of plasma retinol converted from beta-C decreased by 135 microg/L in the beta-C deficiency group, which were much lower than 276 - 306 microg/L in other four beta-C supplement groups (P < 0.01). Intrinsic damage of DNA was more severe in the group of beta-C deficiency than the groups supplemented with beta-C (P < 0.01). The lower DNA oxidative damage of lymphocyte, which was induced by H2O2, was found in 4.28 mg/(kg x d) group than deficiency and other supplement groups (P < 0.05). O6-Methyl-guanine of the supplement groups was lower than the beta-C deficient group at the 6th week and 8th week (P < 0.05). O6-Methyl-guanine did not decreasing with the dose increasing and the lowest in the 4.28mg/(kg x d) group.

Beta-C or retinol deficiency and over intake such as 15.0 mg/(kg x d) as well might cause or promote DNA damage, and a moderate amount such as 4.280 mg/(kg x d) could improve antioxidative and decrease DNA damage effectively.