[Effect of different dosage of vitamin A supplement on anti-oxidative activity and the fluidity of erythrocyte membrane in rats].
OBJECTIVE
To investigating the effect of vitamin A (VA)at different dosage of vitamin A on anti-oxidative activity and the fluidity of erythrocyte membrane in rats and safe dosage.


METHODS
Wistar rats selected for VA supplement trial were randomly divided into four groups. The first group was no VA supplement as a control, and the second, third, forth groups were daily supplemented with VA 11.43, 42.86 and 142.86 microg RE/kg respectively. The trial lasted 8 weeks. Vitamin A was dissolved in soybean oil and daily given to animals by gavage. The blood samples were collected at the end of the trial. The level of plasma VA was analyzed by fluorescent spectrometry. SOD, GSH and MDA in plasma were analyzed. The blood erythrocyte membrane fluidity was detected by fluorescence polarization method.


RESULTS
The results showed that plasma retinol levels increased with increase of vitamin A. After 8 week supplement, SOD activities in the second and the third groups were lower than those of the first and the fourth group (P < 0.01), which was the highest in the four groups (P < 0.01). The level of plasma MDA in the third was the lowest (P 0.01). GSH-Px activity was higher in the third group than other three groups (P < 0.01). Moreover, P (fluorescence polarization) was lower in 42.86 microg RE/kg group than other three groups, and P significantly increased in the fourth group (P < 0.01), which indicates that the erythrocyte membrane fluidity increased significantly after 42.86 microg RE/kg vitamin A supplement.


CONCLUSIONS
The supplement of 42.86 microg RE/kg VA could improve anti-oxidative activity and enhance erythrocyte membrane fluidity. Overtake vitamin A could produce a poisoning effect and a stronger oxidative damage.
Institute of Human Nutrition, Medical College of Qingdao University, Qingdao 266003, China.
Lei
L
Han
Aiguo
A
Ma
Yan
Y
Zhang
D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004910:Erythrocyte Membrane / Q000187:drug effects* / Q000502:physiology; D005260:Female; D005979:Glutathione Peroxidase / Q000097:blood; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D008560:Membrane Fluidity / Q000187:drug effects*; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D013482:Superoxide Dismutase / Q000097:blood; D014801:Vitamin A / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*
D000975:Antioxidants; D014801:Vitamin A; D008315:Malondialdehyde; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase