| Objective To investigate the biochemical metabolism and antioxidative activities of ratinol and P-carotene with Vit Arious dosage in rats.Method (1)Animals and groups: retinol supplementation; 56 Wistar rats , 65 -85g body weight were randomly divided into four groups, each of which has 14 rats. The first group (Vit A1) was no retinol. The second (Vit A2) , third (Vit A3) and forth (Vit A4) groups were supplemented with 11. 43, 42. 86 and 142. 86ugRE/kg · d respectively. β-car-otene supplementation; 70 Wistar rats, 200-220g body weight were randomly divided into five groups, each of which has 14 rats . The first group(β-carotene 1)was deprived from P-carotene. The second (P-carotene 2),third(β-carotene 3) , forth ( β-carotene 4) and fifth (β-carotene 5) group were supplemented with 0. 071, 0. 355, 4. 28 and 15mg/kg · d respectively. Rats were eaten by the same food. Vitamin A and P-carotene were dissolved in soybean oil and daily given to animals by gavage. The supplemented period was 8 weeks. The faceses and urine were collected once a week. The blood , liver and adipose tissue were taken. The plasma, lymphocyte and erythrocyte were separated and kept at -20℃. (2) The content of Vit A and β-C in tissues and plasma were measured by fluoresce and spec-trophoto meter method. SOD,GSH and MDA in plasma were analyzed, DN A damage were analyzed by SCGE, O6 -methylguanine was analyzed by high performance capillary zone e-lectrophoresis . The blood erythrocyte membrance fluidity were detected by fluorescence polarization method.Results (1) The results of biochemical metabolism showed that the plasma concentrations of retinol increased by separately 15. 7%,48. 3% and 64. 0% in supplement groups compared with Vit A deficient group; while the plasma levels of Vit A in four p-carotene supplemented groups increased by separately 114.1%,126. 7%,117. 8% and 104. 4% over the deprived p-carotene, P<0. 01. The plasma p-carotene was not detected in all groups . The retinol level of liver in the 4th group supplemented with Vit A was the highest among all four groups. While the retinol level in the first and second group supplemented with P-carotene was lower than other groups. The storage of Vit A in liver kept at a high level when the supplyment dose reached 0. 355mg/kg · d . The Vit A content in excrement inthe 1th group gradually decreased and the 2th , the 3th and the 4th gradually increased during the trial period. The similar results of Vit A level in b-carotene supplementation happened to be decreased in the 1th group and increased in the 2th ,the 3th , the 4th and the 5th group. (2) The result of antioxidant damage showe that SOD and MDA was the lower supplemented with 42. 86ugRE/kg · d retinol , GSH-Px and the fluorescence polarization were higher than other groups while SOD and MDA were lower in the group supplemented with 4. 28 mg/kg · d b-carotene and GSH-Px and the fluorescence polarization was much higer than other groups. (3) There was significant difference in orginal damage to DNA(P<0. 01) in peripheral lymphocytes in all groups for Vit A and b-carotene supplementation. . There was a significant decrease of DNA damage in peripheral lymphocytes induced by 5umol/L, 10umol/L, 25umol/L of H2O2 in 3th group of Vit A, and in 4th group of b-carotene , P<0. 01. The urine levels of O6-methylguanine in the 1th and the 2th of Vit A supplementation group and 1th b-carotene group were higher than other groups.Conclusion (1)The enough intake of vitamin A and β-carotene can need the requirements of human body and keep the plasma level of retinol and the storage of liver. (2)The supplementation of 42. 86ugRE/kg · d and 4. 28mg/kg · d could increase antioxidative activities and the erythrocyte membrane fluidity, and reduce the DNA oxidative damage. Moreover,the overtake of Vit A could produce a strong poisoning effect,but higher intake of β-carotene did not show any antioxidative activity.
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