Non-enzymatic lipid peroxidation of microsomes and mitochondria from liver, heart and brain of the bird Lonchura striata: Relationship with fatty acid composition.

GUTIÉRREZ AM; REBOREDO GR; MOSCA SM; CATALÁ A

COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR AND INTEGRATIVE PHYSIOLOGY

Elsevier

Año: 2007 vol. 146 p. 415 - 421

1095-6433

The aim of this study was to examine the fatty acid composition and non enzymatic lipid peroxidation in mitochondria and microsomes obtained from liver, heart and brain of Lonchura Striata var. domestica. In all tissues studied the fatty acid composition of mitochondria and microsomes was tissue-dependent. Palmitic (C16:0) and estearic (C18:0) were the saturated fatty acids most abundant in total lipids of mitochondria and microsomes from all tissues studied. The percentage of total unsaturated fatty acid was approximately 30-60 % in liver, heart and brain mitochondria and microsomes, being oleic acid the predominant. Brain mitochondria and both organelles of liver exhibited the highest percentage of polyunsaturated fatty acid (30 and 18%, respectively). The percentage of arachidonic acid (C20:4n6) was 7% in mitochondria of liver and brain and 3% in heart mitochondria. The percentage of docosahexanoic acid (C22:6n3) was 8% in brain mitochondria and approximately 2-3% in heart and liver mitochondria. The peroxidizability index of brain mitochondria was 2 times higher that liver mitochondria and 3 times higher that heart mitochondria. The PI of liver microsomes was 3 and 1.4 times higher than heart and brain microsomes, respectively. Incubation of organelles whit ascorbate –Fe2+ at 37°C caused a stimulation of lipid peroxidation as indicated by the increase in light emission: chemiluminescence and the decrease of  C20:4n6 and C22:6n3 in brain and liver mitochondria and liver microsomes. Statistically significant differences in the percentage of both peroxidable fatty acids C20:4n6 and C22:6n3 were not observed in brain microsomes and both organelles from heart and this was coincident with the absence of lipid peroxidation stimulation. These results indicate: 1) the peroxidizability index of organelles from all tissues analyzed positively correlate with the level of long chain polyunsaturated fatty acids and light emission level. 2) the lower sensitivity to lipid peroxidation detected in heart organelles would contribute to the protection of that tissue against oxidative damage and preservation of cardiac function.