Oleic acid incorporation protects cultured hamster fibroblasts from oxygen-induced cytotoxicity

The effects of oleic, linoleic and arachidonic acid on oxygen toxicity were evaluated in cultured hamster fibroblasts. Each fatty acid was incorporated separately using a protocol that resulted in dose-dependent increases in the respective cellular fatty acid content to as much as 20-fold greater than unsupplemented controls. Linoleic acid produced no changes in cell survival after 48 h treatment with 95% oxygen, regardless of fatty acid content of the cells. Oleic acid incorporation resulted in a dose-dependent increase in cell survival at 48 h in 95% oxygen, whereas arachidonic acid incorporation resulted in a dose-dependent decrease in cell survival at 48 h in 95% oxygen. No significant differences in amounts of linoleic or arachidonic acids were detected in control, oleic acid- enriched or linoleic acid-enriched cells during oxygen exposure. In cells enriched with arachidonic acid, exposure to oxygen significantly reduced the amounts of linoleic and arachidonic acid to 79 and 84%, respectively, of the amounts found in air-exposed cells. The results indicate that oleic acid incorporation into cells provides protection against 95% oxygen-induced cytotoxicity. In contrast, arachidonic acid incorporation led to sensitization of cells to 95% oxygen-induced cytotoxicity that was accompanied by a loss of polyunsaturated fatty acids. As a result, it would appear that in situations of increased oxidative stress, high monounsaturated fatty acid diets that increase cellular oleic acid content may provide a protective environment compared with high polyunsaturated fatty acid diets that increase cellular arachidonic acid content.