Study Of Probucol On Peripheral Blood CD4+CD25+Regulatory T Cells Levels And Function In Atherosclerotic Rabbits

1. BackgroundAtherosclerosis (Atherosclerosis, AS) is the pathological basis of most cardiovascular events, also one of the most dangerous threats to human health and survival. Depth research of atherosclerosis pathogenesis, diagnosis and treatment has become a major issue worldwide. Currently, Statins are commonly used in clinical for stabilizing plaque, anti-inflammatory, anti-AS effect, however, the drug can only prevent coronary events by 30%, treatment is still poor in some AS patients requiring strengthen treatment or replacement therapy. Probucol is one of the most promising drugs, as deepening study of its pharmacological effects in recent years, found that Probucol have a lipid-lowering, anti-inflammatory, antioxidant and anti-atherosclerotic effect to prevent or delay the occurrence and development of AS. But, the specific effect of the drug is still controversial.2. ObjectiveWe set up atherosclerotic rabbit model for study, and observed the function of lipids, Regulatory T cells levels in the AS formation, and analyzed the influences of Probucol to these above indicators at AS state, so as to explore the new mechanism of Probucol anti-atherosclerosis providing experimental evidence for the clinical application of the drug more widely.3. Methods18 Japanese rabbits were randomly divided into several groups.(1) Normal control group (n=6):Fed with common diet;(2) Atherosclerosis group (n=6):Fed with high fat and high cholesterol diet;(3) Probucol group (n=6):gave Probucol 500 mg/(kg·d) on the basis of feeding with high fat and high cholesterol diet. Respectively took blood to measure the level of Total Cholesterol (TC), Triglyceride (TG), Low-density Lipoprotein Cholesterol (LDL-C) and High-density Lipoprotein Cholesterol (HDL-C) with Enzymatic method 0 weeks,4 weeks and 16 weeks later. Used flow cytometry to detect the CD4+CD25+Regulatory T cell numbers in peripheral blood. Measured serum interleukin-10 (Interleukin 10, IL-10) and transforming growth factorβ(TGF-β) levels in double antibody enzyme linked immunosorbent assay. Observed Atherosclerotic plaque morphological changes in the aorta HE staining.4. Results① Took statistical analysis in three groups of 6 rabbits at the end of the experiment. Rabbits weight heavier than before in each group, but the difference was not statistically significant (P> 0.05). ② Feeding with high fat, high Cholesterol diet, serum lipids (TG, TC, LDL-C,HDL-C, VLDL-C) of rabbits in atherosclerosis group and Probucol group was significantly increased compared with the control group at 4 weeks and 6 weeks(P <0.05). Serum lipids in Probucol group was low than Atherosclerosis group, but not significant different when it was 4weeks latter (P>0.05), while the difference was evident and significant 16 weeks latter (P<0.05). ③Watched the aorta gross specimen and found that intimal was smooth, complete and elastic in control group; There were uneven thickness, elastic reducing, multiple lipid profile, partial fusion, and a small portion of the visible plaque with the whole aorta in atherosclerosis group; Uneven thickness, visible fatty streaks, a small part of the integration, no plaque while in Probucol group. ④Serum group IL-10 and TGF-β were almost the same with blank. High fat group lower than blank in 16th week with statistics meanings (P<0.05), and Probucol group were higher than blank in 16th week with statistics meanings (P<0.05). ⑤ At the end of 16th week, in peripheral blood, proportion of CD4+CD25+Regulatory T cell in leukocyte were significantly different with statistics meanings(P<0.05); the differences between blank and atherosclerosis group had statistics meanings (P<0.05),and Probucol group has higher value than above two with statistics meanings (P<0.05).5.Conclusion1) Probucol could decrease the TC、LDL-C、HDL-C、VLDL-C in atherosclerotic rabbit serum.2) Number and function of CD4+CD25+Regulatory T cell in atherosclerotic rabbits droped like human, which means rabbits can be used as animal models to study the pathophysiology and drug treatment of atherosclerotic.3) Probucol works against AS by increasing CD4+CD25+Regulatory T cell level of atherosclerotic rabbits.