Comparison of atherosclerosis between ApoE and LDL-R knockout mice in different diet by vivo ultrasound biomicroscopy

Objective To evaluate the different change in atherosclerosis between apolipoprotein E knockout (ApoE-/-) mice and low density lipoprotein receptor knockout (LDL-R-/-) mice in different diet by vivo ultrasound biomicroscopy(UBM). Methods Thirty-two 8 weeks age ApoE-/- mice and twenty-eight 20 weeks age LDL-R-/- mice were selected, and each mouse model were divided into four groups randomly according to weight. Two groups of each model were fed with normal diet for 8 weeks and 16 weeks respectively as general groups, and two other groups were fed with west diet as high-fat groups. Intima-media thickness(IMT) in the aortic root of all groups were assessed by Vevo 770 UBM, and all measurements of UBM were compared with histopathology and blood-fat. Results ①Thicken wall or plaque in aortic root showed by UBM and histopathology could be found in ApoE-/- mice in all diet conditions, but the changes in LDL-R-/- mice only could be found in high-fat diet conditions; ②IMT of ApoE-/- mice measured in histopathology were significantly higher than LDL-R-/- mice in all diet condition (P<0.05), but in UBM, the IMT of ApoE-/- mice showed significantly higher than that of LDL-R-/- mice only in general diet groups and 8 weeks high-fat diet group (P<0.05); ③In blood-fat, the total cholesterol (TC) in ApoE-/- mice were significantly higher than that of LDL-R-/- mice in all diet conditions (P<0.05). But triglyceride (TG) was higher only in general diet when it was compared between ApoE-/- mice and LDL-R-/- mice. Conclusions It is recommend to select ApoE-/- mice as animal model in atherosclerosis study rather than LDL-R-/- mice, because the higher serum TC and higher susceptible of atherosclerosis in ApoE-/- mice. The west diet is necessary if LDL-R-/- mice was used to atherosclerosis study. Key words: Ultrasonography; Ultrasound biomicroscopy; Mice, knock out; Apolipoproteins E; Low density lipoprotein receptor; Atherosclerosis