Cholesterol Has an Inflammatory Influence in the Effects of Fats on Metabolism in Endotoxemic Rats

Authors: HALİT TANJU BESLER, ROBERT FRANCIS GRIMBLE

Abstract: We showed that butter suppresses metabolic responses to endotoxin in Wistar rats. Responses included increases in plasma caeruloplasmin and liver zinc and protein concentrations, and decreases in plasma zinc and albumin concentration. However, butter lost its suppressive effect at dietary concentrations above 90g/kg diet. The present study examined whether this phenomenon was due to the total dietary cholesterol intake rather than the intrinsic fatty acid composition of butter. Rats received diets, for four weeks, containing either 100g/kg corn oil, 90 g/kg butter, 190g/kg butter, or 90 g/kg butter supplemented with cholesterol to render the latter two diets identical in cholesterol content. All butter diets contained 10g/kg corn oil. Rats received an 800 µg/kg sub-cutaneous injection of E. coli endotoxin. Twenty-four hour post-injection measurement of plasma, cholesterol, albumin, and zinc, and liver cholesterol, glutathione, protein, and zinc was performed. The values were compared with those obtained from pair-fed controls. In rats fed butter (90g/kg), endotoxin had no effect except on liver glutathione, which increased by 85%. ln rats fed corn oil, butter (190g/kg) or butter (90g/kg) supplemented with cholesterol, the liver concentration of zinc increased by 20, 21 and 18% respectively, and that of protein increased by 30, 29 and 23% respectively. Cholesterol increased by 56, 35 and 14% respectively. Glutathione increased by 230, 38, and 65% respectively. In rats fed the diet containing butter (90g/kg), endotoxin had no effect on any of the parameters measured in plasma. However, in the three other dietary groups described above, the zinc concentration decreased by 38, 29 and 19% respectively, albumin decreased by 28, 20 and 15% respectively, caeruloplasmin increased by 142, 83, and 83%, and cholesterol increased by 91, 50 and 51% respectively. The results suggest that butter exerts two opposing influences of inflammation: a pro-inflammatory effect due to its cholesterol content and an anti-inflammatory influence which may be due to its fatty acid composition.

Keywords: Cholesterol, endotoxin, rats, zinc, protein, lipid, metabolism.

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