Establishment and Evaluation of an Animal Model for Atherosclerosis in aopE~(-/-) Mice Induced by Chronic Psychological Stress

Objective To establish an ideal animal model for atherosclerosis in aopE-/-mice induced by chronic psychological stress.Methods Eighty male apoE-/-mice were divided into groups of control and chronic psychological stress.The stress scheme was slightly modified and consisted of the following:two periods of continuous overnight illumination;two periods(7 and 17 h) of 45 degrees cage tile,two periods(9 and 15 h) of intermittent sound(a tone of 70 dB) and two periods of exposure to rat odour.The stressed mice received this stress protocol for 0,4,8 and 12 weeks(n=10 each group).The control mice were housed under identical conditions in a separate room,and had no contact with the stressed animals.All mice were fed a high-fat,high-cholesterol(atherogenic) diet containing 5%(wt/wt) fat and 1.0% cholesterol.The plasma level of TC,TG,HDL and LDL were measured by ELISA using commercially available kits,the splasma corticosterone concentration was determined by solid-phase 125I radioimmunoassay using a commercially available reagent kit,and the lesion areas in aortic sinus were stained with Oil red O and were quantified with IMAGEPRO PLUS.Results(1) Compared with the control group,the level of TC、TG and LDLC in hyperlipidemia group were higher(all P0.05);(2) After 4,8 and 12 weeks of sress,the corticosterone concentration was significantly higher in the chronic psychological stress group than that in the control group(P0.05,P0.01,P0.001,respectively);(3) The atherosclerosis lesions in aortic sinuses of the stressed group mice were significantly increased linearly in response to duration of chronic psychological stress exposure(all P0.01).Conclusion We constructed an ideal chronic psychological stress atherosclerosis apoE-/-mice model successfully.