The Impact of Cholesterol Diet on NPC1L1 and ABCG5 Transpoters and Some Biochemical Parameters in Mouse

Cholesterol homeostasis in the body is controlled mainly by endogenous synthesis, intestinal absorption, and hepatic excretion. Changes in cholesterol absorption and hepatic excretion were reflected by changes in major transporters: ATP-binding cassette G5/G8 (Abcg5/8) and Nieman Pick C1 like 1 Protein (Npc1l1). The aim of our study is to investigate the impact of cholesterol diet on those transporters. Eight (8) weeks male mice have been used, fed during fifteen (15) days and divided into two (2) groups: a control group of (15) mice fed with standard diet and other (15) mice fed with 5%cholesterol diet (second group) .The dosage of excreted cholesterol in feces was determined by gas chromatography coupled with mass spectrometry. Concentration of total cholesterol and triglycerides in the plasma and in the liver is determined by enzyme assay.The expression of mRNA was quantitatively analyzed by RT-PCR. In the jejunum as in the liver of mice subjected to 5% cholesterol diet the RT-PCR revealed the induction of the gene encoding Abcg5 expression. The level of Npc1l1 protein, involved in the intestinal uptake of cholesterol was decreased significantly in mice subjected to 5% cholesterol diet. In those mice, the level of phospholipids has increased, but the rate of triglycerides does not vary. Similarly the masses of livers of mice of that group have increased sharply. The plasma concentration of transaminases, confirmed the development of steatosis. This may explain partially, why mice subjected to 5% cholesterol diet did not develop the syndrome of high cholesterol.