Complex modulation of cytokine induction by endotoxin and tumour necrosis factor from peritoneal macrophages of rats by diets containing fats of different saturated, monounsaturated and polyunsaturated fatty acid composition.

1. Responses to cytokines and other inflammatory stimuli have been shown to be enhanced by fats rich in n-6 polyunsaturated fatty acids and suppressed by fats rich in n-3 polyunsaturated fatty acids and oleic acid or poor in n-6 polyunsaturated fatty acids. 2. Corn oil is rich and coconut oil, olive oil and butter are poor in n-6 polyunsaturated fatty acids. Olive oil and butter are rich in oleic acid. Fish oil is rich in n-3 polyunsaturated fatty acids. 3. The present study examines the effects of feeding standard chow or corn, coconut, fish and olive oils and butter for 4 and 8 weeks on subsequent cytokine production by peritoneal macrophages of rats. 4. Tumour necrosis factor production in response to a lipopolysaccharide stimulus and interleukin-1 and interleukin-6 production in response to a tumour necrosis factor challenge were studied. 5. All fats produced a small, but statistically insignificant, reduction in tumour necrosis factor production, which was greatest for olive oil at 8 weeks. 6. After 4 weeks, fish and olive oil significantly reduced interleukin-1 production. After 8 weeks, coconut oil suppressed production of the cytokine, and the inhibitory effect of fish oil was still apparent. After 8 weeks, corn and olive oil enhanced interleukin-1 production. 7. After 4 weeks of feeding, fish and olive oil enhanced interleukin-6 production. After 8 weeks, the enhancement by these fats increased, and corn oil and butter also enhanced production. Coconut oil produced no modulatory effect.(ABSTRACT TRUNCATED AT 250 WORDS)