黄芪水提取物对载脂蛋白E基因敲除小鼠动脉粥样硬化斑块部位基质金属蛋白酶-9表达及斑块形成的影响

Effects of astragali radix extract on matrix metalloproteinase 9 expression and atheroscierotic plaque formation in aorta of apolipoprotein E deficient mice fed with high fat diet

目的探讨黄芪水提取物对载脂蛋白E基因敲除（ApoE^-/-）小鼠主动脉粥样硬化斑块部位基质金属蛋白酶-9（MMP-9）表达及斑块形成的影响。方法将48只8周龄雄性ApoE^-/-小鼠给予高脂饮食喂养，小鼠20周龄时根据随机表按照完全随机法分为4组各12只，即对照组、阿托伐他汀组、黄芪水提取物低剂量组及黄芪水提取物高剂量组。对照组给予生理盐水0．2ml／d，阿托伐他汀组给予阿托伐他汀10mg·b^-1·d^-1，黄芪水提取物低剂量给予黄芪水提取物1．25g·kg^-1·d^-1、黄芪水提取物高剂量给予黄芪水提取物5g·kg^-1·d^-1灌胃。予给药12周末处死各组小鼠。应用ELISA法测定血清氧化低密度脂蛋白（oxLDL）含量；HE染色、油红O染色观察小鼠主动脉粥样斑块内脂质的形成；用免疫荧光、免疫组化染色法检测观察粥样斑块部位巨噬细胞浸润水平及MMP-9表达。结果黄芪水提取物明显降低ApoE^-/-小鼠，其中黄芪水提取物高剂量组血清oxLDL含量明显低于对照组[（5．2±6．1）μg／ml比（15．8±5．4）μg／ml，P〈0．01]；与对照组比较，黄芪水提取物高剂量组ApoE^-/-小鼠动脉粥样斑块面积明显减小（17．24％±4．22％比49．87％±9．37％，P〈0．01），动脉管壁斑块弥漫程度较轻（P〈0．01）。黄芪水提取物高剂量组斑块中Mac3表达低于对照组（P〈0．01）；黄芪水提取物高剂量组与对照组主动脉斑块中MMP-9阳性表达面积平均吸光度值（MA）分别为0．0154±0．0014与0．0263±0．0065（P〈0．01）。结论黄芪水提取物能够抑制ApoE^-/-小鼠动脉MMP-9表达，延缓动脉粥样硬化斑块形成。其机制可能是通过降低ApoE^-/-小鼠血清oxLDL水平，抑制巨噬细胞的浸润、迁移及分泌MMP．9，从而抑制斑块形成。

Objective To explore the effects of astragali radix extract on the expressions of matrix metalloproteinase 9 （MMP-9） and the formation of atherosclerotic plaque in aortic atherosclerotic plaques of apolipoprotein E-deficient mice （ApoE -/- ） . Methods Male 8-week-old ApoE-/- mice fed with high fat diet were randomly divided into four groups （n = 12 each） ： control group （saline 0. 2 ml/d）, atorvastatin group （atorvastatin 10 mg · kg^-1 · d^-1 ） , low-dose astragali radix extract group （1.25 g · kg^-1 · d^-1） and high-dose astragali radix extract group（5 g · kg^-1 · d^-1 ）. After 12 weeks, serum oxLDL was measured by the method of ELISA. The formation of atherosclerotic plaque was determined in HE and oil red O stained aortic slice. The expressions of macrophage and MMP-9 in the aortic plaque were detected by immune fluorescence and immunohistochemistry staining method. Results Similarly as atorvastatin, astragali radix extract significantly decreased the level of serum oxLDL in ApoE -/- mice in a dose-dependent manner. The level of oxLDL in the high-dose astragali radix extract group [ （5.2 ± 6. 1 ） μg/ml ] was significantly lower than that in the control group [ （ 15.8 ±5.4 ）μg/ml, P 〈 0. 01]. The area of atherosclerosis plaques was smaller （ 17.24% ±4.22% vs. 49.87% ±9.37% ,P 〈0.01 ） and the penetration degree of plaques in the arterial wall was relieved in the high-dose astragali radix extract group compared to those in the control group （P 〈 0. 01 ）. The expressions of Mac3 in atherosclerosis plaques of the high-dose astragali radix extract group was also significantly lower than in the control group （P 〈 0. 01 ）. The mean absorbanee value of the expression of MMP-9 in the high-dose astragali radix extract group （0. 0154 ± 0. 0014）was significantly lower than that in the control group （ 0. 0263 ±0. 0065 ） （ P 〈 0. 01 ）. Conclusions Similar as atorvastatin, astragali radix extract can dose-dependently inhibit the expression of MMP-9 and the formation of the atherosclerotic plaque in ApoE-/- mouse, probably by reducing the serum oxLDL, inhibiting macrophage infiltration, migration and secretion of MMP-9 .