Characterization of NPC1L1 gene-modified Ldlr^mt mice. (A) Cholesterol absorption was examined in 10- to 12-week-old male I⁺L⁻, I⁺L⁺, I⁻L⁻, and I⁻L⁺ mice. [³H]cholesterol concentrations in plasma, liver, and plasma plus liver were examined 2 hours after the administration of [³H]cholesterol-containing emulsion. (B) Biliary concentrations of cholesterol, bile acids, and phospholipids were examined in 10- to 12-week-old male I⁺L⁻, I⁺L⁺, I⁻L⁻, and I⁻L⁺ mice. Bar graphs represent the mean ± S.D. The dots on bar graphs represent each individual data point (n = 3: no statistical analysis was performed in Fig. 2 because the sample size was too small to justify statistical testing for multiple comparisons, although the observed differences among genotypes were sufficiently clear to validate the constructed mouse models).

Plasma lipid profiles in NPC1L1 gene–modified Ldlr^mt mice after WD feeding. Cholesterol (A) and triglyceride (B) concentrations in plasma from male mice (initially 6–8 weeks old) fed with a WD for 20 weeks in the absence (−) or presence (+) of ezetimibe (Eze). Bar graphs represent the mean ± S.D. The dots on bar graphs represent each individual data point [n = 15, I⁺L⁻ Eze (−) mice; n = 8, I⁺L⁻ Eze (+) mice; n = 9, I⁺L⁺ Eze (−) mice; n = 4, I⁺L⁺ Eze (+) mice; n = 12, I⁻L⁻ Eze (−) mice; n = 4, I⁻L⁻ Eze (+) mice; n = 7, I⁻L⁺ Eze (−) mice; n = 4, I⁻L⁺ Eze (+) mice]. *P < 0.05; **P < 0.01, significantly different by Dunnett’s test comparing I⁺L⁺ Eze (−) mice, I⁻L⁻ Eze (−) mice, and I⁻L⁺ Eze (−) mice with I⁺L⁻ Eze (−) mice. †P < 0.05; ††P < 0.01, significantly different by Student’s t test comparing two groups [Eze (−) and Eze (+)] in each genotype. N.S., not significantly different between the groups. Cholesterol (C) and triglyceride (D) concentrations in lipoprotein fractions collected from male mice (initially, 6–8 weeks old) fed with a WD for 20 weeks in the absence (left panel) or presence (right panel) of ezetimibe. Representative lipoprotein profiles from at least two independent experiments are shown.

Hepatic lipid concentrations in NPC1L1 gene–modified Ldlr^mt mice after WD feeding. Cholesterol (A) and triglyceride (B) concentrations in the liver from male mice (initially, 6–8 weeks old) fed with a WD for 20 weeks in the absence (−) or presence (+) of ezetimibe (Eze). Bar graphs represent the mean ± S.D. The dots on bar graphs represent each individual data point (n = 4). **P < 0.01, significantly different by Dunnett’s test comparing I⁺L⁺ Eze (−) mice, I⁻L⁻ Eze (−) mice, and I⁻L⁺ Eze (−) mice with I⁺L⁻ Eze (−) mice. ††P < 0.01, significantly different by Student’s t test comparing two groups [Eze (−) and Eze (+)] in each genotype. N.S., not significantly different between the groups.

Atherosclerotic lesions of the aorta in NPC1L1 gene–modified Ldlr^mt mice after WD feeding. The excised aorta from the mice analyzed in Fig. 3 was opened longitudinally, followed by Oil Red O staining. (A) Representative pictures (top panels) and percentage of areas of intimal atherosclerotic plaque lesions of the aortic wall (bottom graph) are shown. Bar graphs represent the mean ± S.D. The dots on bar graphs represent each individual data point [n = 15, I⁺L⁻ Eze (−) mice; n = 8, I⁺L⁻ Eze (+) mice; n = 9, I⁺L⁺ Eze (−) mice; n = 4, I⁺L⁺ Eze (+) mice; n = 12, I⁻L⁻ Eze (−) mice; n = 4, I⁻L⁻ Eze (+) mice; n = 7, I⁻L⁺ Eze (−) mice; n = 4, I⁻L⁺ Eze (+) mice]. **P < 0.01, significantly different by Dunnett’s test comparing I⁺L⁺ Eze (−) mice, I⁻L⁻ Eze (−) mice, and I⁻L⁺ Eze (−) mice with I⁺L⁻ Eze (−) mice. ††P < 0.01, significantly different by Student’s t test comparing two groups [Eze (−) and Eze (+)] in each genotype. N.D., not detected. (B and C) Correlation of the percentage of areas of intimal atherosclerotic plaque lesions with plasma concentrations of cholesterol (B) and triglyceride (C). Correlation analysis was performed using Pearson’s method. R value represents Pearson’s correlation coefficient.