补充β-胡萝卜素对大鼠抗氧化能力及红细胞膜流动性影响的研究

目的:通过补充不同剂量β-胡萝卜素(β-C),探讨其对机体抗氧化能力和红细胞膜流动性的影响。方法:Wistar大鼠分为β-C缺乏组(β-C1组),每天补充β-C0.071(β-C2组),0.355(β-C3组),4.28(β-C4组)和15.0mg/kg(β-C5组)4个剂量组,均喂不含VA饲料8w。采用荧光法测定大鼠血浆和肝脏中VA含量,分析血液中SOD、MDA和GSH-Px含量及活性,用荧光偏振度P值和微粘度η值评价红细胞膜的流动性。结果:补充8w干预后,β-C缺乏组大鼠血浆中VA含量为135μg/L,明显低于β-C补充各组(P<0.01),肝脏VA水平仅为0.761μg/g;β-C补充达15.0mg/(kg·d)时,肝脏VA储存量最高,分别是β-C1组和β-C2组的7.7倍(P<0.01)和3.86倍(P<0.01)。抗氧化能力分析结果显示,4.28mg/(kg·d)组血浆中SOD的含量较其他4组均降低(P<0.05),GSH-Px活性明显升高,脂质过氧化物MDA的含量明显下降(P<0.01),红细胞膜流动性明显提高,表现为荧光偏振度P和微粘度η值均明显低于β-C1组、β-C2组和β-C5组(P<0.05)。结论:大鼠每天摄入0.355mg/(kg·d)以上剂量的β-C,即可满足机体对视黄醇的生理需要并在肝脏中保持一定量的储存,4.28mg/(kg·d)的β-C补充则能够发挥较好的抗氧化作用,提高红细胞膜的流动性,而过高剂量补充无明显效果。

EFFECT OF β -CAROTENE SUPPLEMENTATION ON THE ANTI-OXIDATIVE ACTIVITY AND THE FLUIDITY OF ERYTHROCYTE MEMBRANE IN RATS

Objective: To investigate the effect of supplementing β-carotene on anti-oxidative activity and the fluidity of erythrocyte membrane in rats. Methods: Wistar rats were randomly divided into five groups. The first group was deprived of β-carotene, and the 2nd to 5th groups were daily supplemented with 0.071, 0.355, 4.28 and 15.0 mg/kg β-carotene respectively. All rats were fed without retinol for 8 weeks. The plasma and hepatic retinol contents were measured by fluorescent spectrometry. Levels of plasma SOD and GSH-Px activity, and MDA were analyzed.The fluidity of erythrocyte membrane was evaluated by fluorescence polarization (P) and microviscosity (η). Results: After 8 w supplementation, the plasma levels of retinol decreased by 135 μg/L and 0.761 μg/g in the liver of rats with β-carotene(β-C) deficiency, which was lower than other four groups(P<0.01). The highest liver storage (5.876 μg/g ) was in the β-C5 group, about 7.7 times(P<0.01)and 3.86 times(P<0.01)higher than those in the β-C1 and β-C2 groups respectively. The SOD in plasma was lower than other 4 groups(P<0.05), and GSH-Px activity in plasma was much higher, and plasma MDA was lower in 4.28 mg/(kg·d)group than those in other four groups. Moreover, P and η values were lower in 4.28 mg/(kg·d)group than the deficient group, 0.071 and 15.0mg/(kg·d)groups, which indicated the erythrocyte membrane fluidity of rats with supplementing 4.28 mg/(kg·d)β-C was obviously improved. Conclusion: The β-carotene intake of 0.355 mg/(kg·d) or more will meet the physiological need of retinol and moderate storage in the liver of rats; while the 4.28 mg/(kg·d)β-C supplement could enhance anti-oxidative activity and improve erythrocyte membrane fluidity,but over dosage showed no effects.