Addition of vitamin E to long-chain polyunsaturated fatty acid-enriched diets protects neonatal tissue lipids against peroxidation in rats.
BACKGROUND
Tissue 10:4(n-6) and 22:6(n-3) status have been correlated with neonatal development and growth. Artificial formulas for neonates have been supplemented with long chain polyunsaturated fatty acids (LCP) from animal and marine sources which may enhance sensitivity of cellular membranes to oxidative damage. Diet-derived antioxidants like vitamin E play a key role in the protection of tissue lipids against oxidation.


OBJECTIVE
We seek to determine the influence of dietary vitamin E on tissue sensitivity to oxidative stress in rats fed for 4 weeks on diets enriched in (n-3) and (n-6) long-chain polyunsaturated fatty acids.


METHODS
Weanling rats received 10% fat diets that provided 18:1(n-9), 18:2(n-6) and 18:3(n-3) in a similar ratio to that of rat milk (group A), supplemented with fish oil (groups B and B+E) and supplemented with (n-6) and (n-3) LCP from an animal phospholipid concentrate (groups C and C+E). Vitamin E (500 mg vitamin E/kg fat) was added to diets B+E and C+E. Tissue fatty acid content and the activities of catalase, superoxide dismutase, glutathione transferase und glutathione peroxidase in liver and brain were measured. Glutathione status, vitamin E and the production of thiobarbituric acid reactive substances (TBARs) after incubation of erythrocyte, liver and brain lipids with inducers of enzymatic or non-enzymatic lipid peroxidation was measured.


RESULTS
Group B registered significantly lower total superoxide dismutase activity than group B+. Catalase activity was significantly higher in group C than in group C+E. Hepatic total and reduced glutathione levels were decreased in vitamin E supplemented groups compared to unsupplemented ones. TBARs production in erythrocyte lipids was significantly higher in groups B and C compared to vitamin E supplemented groups B+E and C+E.


CONCLUSIONS
This study shows that the addition of vitamin E protected erythrocyte and liver microsome lipids enriched in (n-3) and (n-6) LCP from lipid peroxidation during the postnatal development of rats. The protection was more effectively in group C+E than in group B+E.
Suárez
A
A
Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Granada, E-18071, Granada, Spain. asuarez@platon.ugr.es
Ramírez-Tortosa
M
M
Gil
A
A
Faus
M J
MJ
D000818:Animals; D001923:Brain Chemistry; D002374:Catalase / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D004042:Dietary Fats, Unsaturated / Q000009:adverse effects* / Q000378:metabolism; D004912:Erythrocytes / Q000737:chemistry / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000009:adverse effects* / Q000378:metabolism; D005978:Glutathione / Q000032:analysis; D005979:Glutathione Peroxidase / Q000032:analysis; D015227:Lipid Peroxidation / Q000187:drug effects* / Q000502:physiology; D008099:Liver / Q000737:chemistry / Q000378:metabolism; D008297:Male; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D013482:Superoxide Dismutase / Q000032:analysis; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis; D014810:Vitamin E / Q000008:administration & dosage / Q000494:pharmacology*; D014886:Weaning
D004042:Dietary Fats, Unsaturated; D005231:Fatty Acids, Unsaturated; D017392:Thiobarbituric Acid Reactive Substances; D014810:Vitamin E; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D005978:Glutathione