title: High-dose supplemental selenite to male Syrian hamsters fed hypercholesterolaemic diets alters Ldlr, Abcg8 and Npc1l1 mRNA expression and lowers plasma cholesterol concentrations.
abstract: The aim of the present study was to elucidate possible cholesterol-lowering mechanism(s) of high-dose supplemental Se in the form of selenite, a known hypocholesterolaemic agent. Male Syrian hamsters (four groups, ten per group) were fed semi-purified diets for 4 weeks containing 0.1 % cholesterol and 15 % saturated fat with selenite corresponding to varying levels of Se: (1) Se 0.15 parts per million (ppm), control diet; (2) Se 0.85 ppm; (3) Se 1.7 ppm; (4) Se 3.4 ppm. Lipids were measured in the bile, faeces, liver and plasma. The mRNA expression of several known regulators of cholesterol homeostasis (ATP-binding cassette transporters g5 (Abcg5) and g8 (Abcg8), 7-hydroxylase, 3-hydroxy-3-methylglutaryl-coenzyme A reductase, LDL receptor (LdLr) and Nieman-Pick C1-like 1 protein (Npc1l1)) were measured in the liver and/or jejunum. Oxysterols including 24-(S)-hydroxycholesterol, 25-hydroxycholesterol and 27-hydroxycholesterol (27-OHC) were measured in the liver. Significantly lower total plasma cholesterol concentrations were observed in hamsters consuming the low (0.85 ppm) and high (3.4 ppm) Se doses. The two highest doses of Se resulted in decreased plasma LDL-cholesterol concentrations and increased mRNA levels of hepatic Abcg8, Ldlr and jejunal Ldlr. Higher hepatic 27-OHC and TAG concentrations and lower levels of jejunal Npc1l1 mRNA expression were noted in the 1.7 and 3.4 ppm Se-treated hamsters. Overall, Se-induced tissue changes in mRNA expression including increased hepatic Abcg8 and Ldlr, increased jejunal Ldlr and decreased jejunal Npc1l1, provide further elucidation regarding the hypocholesterolaemic mechanisms of action of Se in the form of selenite.
authors.affiliation: School of Dietetics and Human Nutrition, Macdonald Campus of McGill University, Ste-Anne-de-Bellevue, QC, Canada.
authors.forename: Johanne
authors.initials: J
authors.lastname: Poirier
authors.forename: Kevin A
authors.initials: KA
authors.lastname: Cockell
authors.forename: Kylie A
authors.initials: KA
authors.lastname: Scoggan
authors.forename: W M Nimal
authors.initials: WM
authors.lastname: Ratnayake
authors.forename: Hélène
authors.initials: H
authors.lastname: Rocheleau
authors.forename: Heidi
authors.initials: H
authors.lastname: Gruber
authors.forename: Eleonora
authors.initials: E
authors.lastname: Swist
authors.forename: Philip
authors.initials: P
authors.lastname: Griffin
authors.forename: Claude
authors.initials: C
authors.lastname: Gagnon
authors.forename: Stan
authors.initials: S
authors.lastname: Kubow
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D000924:Anticholesteremic Agents / Q000008:administration & dosage / Q000627:therapeutic use; D002784:Cholesterol / Q000032:analysis / Q000097:blood / Q000378:metabolism; D006224:Cricetinae; D059305:Diet, High-Fat / Q000009:adverse effects; D019587:Dietary Supplements; D005786:Gene Expression Regulation; D006888:Hydroxycholesterols / Q000378:metabolism; D006937:Hypercholesterolemia / Q000097:blood / Q000517:prevention & control*; D007583:Jejunum / Q000378:metabolism; D008099:Liver / Q000201:enzymology / Q000378:metabolism; D008297:Male; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D008647:Mesocricetus; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D011897:Random Allocation; D011973:Receptors, LDL / Q000235:genetics / Q000378:metabolism*; D018038:Sodium Selenite / Q000008:administration & dosage / Q000627:therapeutic use*
chemical_list: D018528:ATP-Binding Cassette Transporters; D000924:Anticholesteremic Agents; D006888:Hydroxycholesterols; D026901:Membrane Transport Proteins; D020033:Protein Isoforms; D012333:RNA, Messenger; D011973:Receptors, LDL; D002784:Cholesterol; D018038:Sodium Selenite