A uniform alteration in serum lipid metabolism occurring during inflammation in mice

The present study was designed to delineate changes in serum lipid levels following various kinds of tissue injury or inflammation such as contact sensitivity to picryl chloride, thermal burn, carrageenin-induced edema, the administration of turpentine oil, Freund's complete adjuvant (FCA), killed Bordetella pertussis (BP) or lipopolysaccharide (LPS). A uniform change in the serum lipid metabolism was observed in mice that received these inflammatory stimuli; that is, increases in total cholesterol, free cholesterol and phospholipid levels, a decrease in the ester ratio and a decline in lecithin: cholesterol acyltransferase activity as well as a decrease in albumin levels, which is an index of the acute-phase response. However, serum triglyceride levels were increased by treatment with the bacterial stimuli (FCA, BP and LPS) but decreased by treatment with the other stimuli. The serum free cholesterol and phospholipid levels were significantly correlated with the intensity of contact sensitivity, which was modified by treatment with cyclophosphamide. Indomethacin or dexamethasone suppressed carrageenin-induced edema and inhibited some of the alterations in lipid metabolism that developed during inflammation because each affected a part of the lipid metabolism. These findings suggest that, like the appearance of acute-phase proteins, the uniform change in serum lipid metabolism may be another sensitive index of the acute inflammatory response.