Effect of cholesterol and 7-βhydroxycholesterol on glutathione status and nitric oxide production in murine peritoneal macrophages

Abstract

Present study was conducted to observe the effect of cholesterol and oxidized cholesterol (7β-hydroxycholesterol, 7β-OH) on the nitric oxide (NO) production and the redox ratio by lipopolysaccharide-stimulated macrophages. Dosedependent decrease in NO levels was seen with both cholesterol and 7β-OH at different incubation intervals (6,12 ,18,24 hr) and concentrations (2.5,5,7.5μg/ml). On comparison, a significant decrease in the NO was observed at 24 hr interval in 7β-OH exposed cells with all respective concentrations of cholesterol. Incubation with 7β-OH also resulted in significant increase in levels of oxidized glutathione (GSSG) and decrease in reduced glutathione (GSH), while cholesterol showed no

effect on GSSG levels. Moreover, GSH levels were lowered only at highest concentration (7.5μg/ml), and at longer incubation intervals (18,24 hr) with cholesterol exposure. This altered the redox status in both cholesterol/7β-OH treated macrophages. Increased redox ratio and decreased NO levels indicated increased oxidative stress and decreased vasodilation

by 7β-OH compared to cholesterol.