The Effects Of Soluble Epoxide Hydrolase Inhibitors On Adipocyte Mediated Reverse Cholesterol Transport

ObjectivesThe purpose of this study was to determine the effect of (soluble epoxide hydrolase inhibitor, sEHi)—t-AUCB on the severity of the atherogenic process in apoE-/-mice with established lesions. We investigated the effects of t-AUCB on multiple steps along the adipocyte-mediated RCT pathway in vivo and observed the influence of mice plasma on adipocyte cholesterol efflux ex vivo. Illustrating the effect of t-AUCB on adipocyte-mediated reverse cholesterol transport (RCT) and possible mechanisms, which contribute to provide the integrated functional evidence that the role of t-AUCB on atherosclerosis.MethodsThirty six apoE-/-mice were randomly divided into3groups:(1) Control group (n=6) were fed with normal diet for9weeks;(2) high-cholesterol diet for9weeks (n=9);(3) high-cholesterol diet for8weeks plus various concentrations t-AUCB (0,5,15,50mg/l) for1week (n=20). We injected the mice intraperitoneally with3H-cholesterol labeled adipocytes. After48hours, plasma, liver, bile and feces were collected for detecting the3H-cholesterol radioactivity. The mice serum was used as the extracellular acceptor. We determined the rate of adipocytes cholesterol efflux mediated by serum from respective groups via liquid scintillation counting. Aortas were then stained with Sudan III and H&E staining. ABCA1,SR-BI, ABCG5and ABCG8mRNA and protein expression in liver and ABCG5and ABCG8mRNA and protein expression in intestine were determined by Realtime-PCR and Western Blot.Results1. The areas of atherosclerosis plaque in both normal diet group and high cholesterol diet group were (25.48±1.86)%,(76.32±5.08)%respectively. Compared with normal diet group, high cholesterol diet group had decreased aortic plaque formation and had statistic significance. The areas of atherosclerosis plaque among t-AUCB0、5、15、50mg/L groups were (76.32±5.08)%,(66.7±3.37)%,(48.56±0.77)%,(36.74±1.64)%respectively. Compared with t-AUCB Omg/L group, t-AUCB attenuated the mice aortic plaque formation in a concentration-dependant manner.2. Compared with normal diet group, the decreased precent of3H-cholesterol radioactivity of plasma, liver, bile and feces in high cholesterol diet group were45%,4.7%,60.8%,57.4%respectively; compared with t-AUCB Omg/L group, the elevated precent of3H-cholesterol radioactivity of plasma among t-AUCB5、15、50mg/L groups were45%,4.7%,60.8%,57.4%respectively in a concentration-dependant manner, the elevated precent of3H-cholesterol radioactivity of liver among t-AUCB5、5、50mg/L groups were38.46%,138%,141% respectively in a concentration-dependant manner, the elevated precent of JH-cholesterol radioactivity of bile among t-AUCB5、15、50mg/L groups are155%,178%,233%respectively in a concentration-dependant manner, the elevated precent of3H-cholesterol radioactivity of bile among t-AUCB5、15、50mg/L groups were65%,161%,226%respectively in a concentration-dependant manner.3. The mice serum of normal diet and high cholesterol diet group mediate adipocyte cholesterol efflux were (8.20±0.88)%and (6.39±1.11)%. Compared with normal diet group, high cholesterol diet group have decreased cholesterol efflux and have statistic significance. Compared with t-AUCB Omg/L group, the cholesterol efflux mediated by the mice serum of t-AUCB5、15、50mg/L groups mediate adipocyte cholesterol efflux were elevated in a concentration-dependant manner and are (6.39±1.11)%,(8.18±0.34),(9.22±1.22)%,(10.81±0.71)%respectively.4. Compared with normal diet group, the expression of ABCG5and ABCG8mRNA and protein in liver and intestine elevated in high cholesterol diet group and had statistic significance. Compared with t-AUCB Omg/L group, the expression of ABCG5and ABCG8mRNA and protein in liver and intestine eleavted among t-AUCB5、15、50mg/L groups and elevated in a concentration-dependant manner, and had decreased the expressions of ABC A1mRNA and protein, had no impact on SR-BI mRNA and protein expression.Conclusions1. High cholesterol diet could increase the the area of aortic atherogenic plaque formation;t-AUCB attenuated the area of aortic atherogenic plaque formation in a concentration-dependant manner.2. High cholesterol diet could slow the rate of adipocyte-mediated RCT in mice;t-AUCB accelerated the rate of adipocyte-mediated RCT in mice in a concentration-dependant manner.3. High cholesterol diet could decrease adipocyte cholesterol efflux mediated by mice serum; t-AUCB increased adipocyte cholesterol efflux mediated by mice serum in a concentration-dependant manner.4.t-AUCB contribute to the adipocyte-mediated RCT was possibly attributed to the decreased adipocytes cholesterol efflux mediated by mice serum, the decreased expressions of hepatic ABCA1mRNA and protein, the increased ABCG5and ABCG8mRNA and protein expressions in liver and intestine.