Hepatic function and lipid metabolism are modulated by short-term feeding of cholesterol oxidation products in rats

Dietary cholesterol oxidation products (COPs) modulate various metabolic processes, particularly lipid metabolism. In this study, we observed that dietary COPs perturbed hepatic function, linoleic acid desaturation, and cholesterol catabolism in rats that were fed with diets containing 0.5% COPs for a short duration (7 days). The rats (age, 8 weeks) were fed American Institute of Nutrition (AIN)-purified diets containing 0.5% cholesterol or 0.5% COPs for 7 days. The glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), and lactate dehydrogenase (LDH) levels were significantly high in rats fed with dietary COPs, but no such increase was observed in rats fed with dietary cholesterol, thereby indicating that dietary COPs may impair the hepatic function. The mRNA expression levels of Delta6 desaturase in the liver were significantly increased by dietary COPs, while these levels were significantly decreased by dietary cholesterol. However, the mRNA expression level of cholesterol 7alpha-hydroxylase (CYP7A1) in the liver was significantly decreased by dietary COPs and significantly increased by dietary cholesterol. Therefore, dietary COPs may modulate lipid metabolic processes such as linoleic acid desaturation and cholesterol catabolism even when they are consumed for a short duration. Hence, processed animal foods containing COPs should be consumed with caution.