Modulation Of Calcification By Acute Serum Amyloid A And Atorvastatin

Objective1.To assess the effect of acute serum amloid A（A-SAA） on ApoE-/-micecalcification and its mechanism.2. To assess the effect of atorvastatin on calcification and its mechanism.Methods1. Twenty-four six weeks old male ApoE-/-mice were fed diets containing45%kcalfrom fat.The mice received diets ad lib for8weeks and had free access to water. Thenthe mice were randomly divided into two groups: regular-chow diet group (n=12) andA-SAA group (n=12)(treated with human recombinant Apo-SAA10μg per day byintraperitoneal injection for7days at the base of regular-chow diet group).The micewere killed respectively during10,14or18weeks old in each group. Aortic sectionswere separated and the calcium deposition was observed under microscope after vonkossa statining. Immunohistochemical staining was performed to visualize theexpresssion of vascular BMP-2. The expression of FetuinA in the liver of mice wasmeasured using western bolt in each group.2. Human Aorta Endothelial Cells (HAECs) were treated with low doseatorvastatin(20umol/L) and high dose atorvastatin(50umol/L).And a control groupwas set.The level of BMP-2, calcium content and AKP activity were measured.3. Twelve six weeks old male ApoE-/-mice were fed diets containing45%kcal fromfat.The mice received diets ad lib for8weeks and had free access to water.Then themice were randomly divided into two groups: atorvastatin group（n=6）(treated withatorvastatin5mg per kg per day by intragastric administration for8weeks) or high fat group (n=6). After8weeks of diet, mice were killed.Then the aortic sections wereseparated and the calcium deposition was observed under microscope after von kossastatining.Immunohistochemical staining was performed to visualize the expresssionsof vascular BMP-2.Results1. Calcium deposition could be observed in the intima and tunica media of the aortain the A-SAA group at10weeks old, and intensive calcium deposition could beobserved in the intima and tunica media of the aorta in the A-SAA group at14and18weeks old. The expression of vascular BMP-2in the regular-chow diet group wasn’tsignificantly different weeks(trend P>0.05), but it was obviously in the A-SAAgroup(trend P <0.05).And at the18weeks age,the expression of vascular BMP-2wassignifcantly higher than the regular chow-diet group(P <0.05).The level of FetuinAin the liver significantly decreased gradually with increasing duration of diet(trend P<0.05), and at the14weeks old, the FetuinA level was significantly lower than theregular-chow diet group(P <0.01).But at the10and18weeks old mice,the FetuinAlevel of the A-SAA group had no significant difference compared with theregular-chow diet group at the same age mice.2. High dose atorvastatin increased HAECs BMP-2expression compared with thecontrol group (P <0.05),but had no significant difference compared with the lowdose group.And high dose atorvastatin further increased the calcium deposits and theactivity of AKP significantly compared with the control group and low doseatorvastatin group(P <0.01,P <0.05).3. The calcium mineral deposits on vascular tissue induced by atorvastatin werestronger than the high fat group(P <0.05).The expression of BMP-2in atorvastatingroup was increased compared with the high fat group(P <0.01). Conclusion1. A-SAA may aggravate the inflammation of blood vessels and induce the secretionof vascular BMP-2and at the same time prevent the expression of FetuinA in the liver,further promote the progression of atherosclerotic plaques and calcium deposits, lastly,promote the occurrence and development of vascular calcification in ApoE-/-mice.2. Atorvastatin may stimulate the HAECs calcification through increasing theexpression of BMP-2and accelerating calcium deposition as well as the activity ofAKP.And atorvastatin may increase the expression of BMP-2and accelerate calciumdeposition of vascular tissue, thus affect calcification of aortic tunica intima.