Influence of long-term supplementation with alpha-linolenic acid on myocardial lipid peroxidation and antioxidative capacity in spontaneously hypertensive rats.
The ischaemic vulnerability of the heart of spontaneously hypertensive rats (SHR) is enhanced after feeding an alpha-linolenic acid (LNA) enriched diet. Because oxygen radical-induced reactions (e.g. lipid peroxidation) are involved in the ischaemic damage, an increased susceptibility of the SHR heart to such damaging reactions might be the reason. As a sign of the enhanced susceptibility to lipid peroxidation of LNA-fed SHR, we found (measured as TBARS) higher plasma and heart lipid peroxide levels (3.84 +/- 0.50 micromol/l vs 2.98 +/- 0.78 micromol/l and 507 +/- 127 nmol/g prot. vs 215 +/- 80 nmol/g prot., respectively) after feeding LNA. Using Fe2+/Vit. C to induce lipid peroxidation in myocardial tissue homogenates, we demonstrated the enhanced susceptibility to lipid peroxidation of the LNA-fed SHR heart (68 +/- 12 nmol/min x g prot. vs 40 +/- 8 nmol/min x g prot.) also in vitro. The myocardial enrichment of n-3 polyunsaturated fatty acids (PUFA) resulting in a higher peroxidation index (PI 227 vs. 170) and the loss in myocardial activities of the antioxidative enzymes (SOD: 76 +/- 24 U x 10(3)/g prot. vs 235 +/- 150 U x 10(3)/g prot.; GSH-Px: 32 +/- 5 U/g prot. vs 110 +/- 30 U/g prot.) by feeding LNA could be the cause of the increase in myocardial susceptibility to lipid peroxidation of PUFA supplemented SHR.
Schimke
I
I
Medizinische Klinik und Poliklinik 1, Universitätsklinikum Charité, Humboldt-Universität zu Berlin, Germany.
Haberland
A
A
Wirth
M
M
Papies
B
B
Moritz
V
V
Baumann
G
G
D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001205:Ascorbic Acid / Q000494:pharmacology; D019587:Dietary Supplements; D005227:Fatty Acids / Q000032:analysis; D005979:Glutathione Peroxidase / Q000187:drug effects / Q000378:metabolism; D005982:Glutathione Transferase / Q000187:drug effects / Q000378:metabolism; D006321:Heart / Q000187:drug effects; D007501:Iron / Q000494:pharmacology; D015227:Lipid Peroxidation / Q000187:drug effects*; D008054:Lipid Peroxides / Q000097:blood; D009206:Myocardium / Q000378:metabolism*; D010743:Phospholipids / Q000737:chemistry / Q000378:metabolism; D051381:Rats; D011918:Rats, Inbred SHR; D013482:Superoxide Dismutase / Q000187:drug effects / Q000378:metabolism; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism*; D017962:alpha-Linolenic Acid / Q000494:pharmacology*
D000975:Antioxidants; D005227:Fatty Acids; D008054:Lipid Peroxides; D010743:Phospholipids; D017392:Thiobarbituric Acid Reactive Substances; D017962:alpha-Linolenic Acid; D007501:Iron; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D005982:Glutathione Transferase; D001205:Ascorbic Acid