动脉粥样硬化大鼠B族Ⅰ型清道夫受体与肾素-血管紧张素系统的表达变化

Study of the Expression of Scavenger Receptor Class B TypeⅠ and Renin Angiotensin System in Atherosclerotic Rats

目的研究动脉粥样硬化大鼠主动脉B族Ⅰ型清道夫受体、血管紧张素Ⅱ1型受体和2型受体表达、血管紧张素Ⅱ水平的变化及其相互作用,探讨动脉粥样硬化的发生机制。方法将18只大鼠随机分为对照组和动脉粥样硬化组,通过高脂喂养12周、主动脉内皮损伤和维生素D3肌肉注射建立大鼠主动脉粥样硬化模型。HE染色和M asson染色观察主动脉管壁结构和粥样硬化斑块的形成情况,放射免疫法检测血管紧张素Ⅱ的水平,免疫组织化学、W estern B lot检测B族Ⅰ型清道夫受体、血管紧张素Ⅱ1型受体和2型受体的蛋白表达,实时定量逆转录聚合酶链反应检测B族Ⅰ型清道夫受体、血管紧张素Ⅱ1型受体和2型受体的mRNA表达,B族Ⅰ型清道夫受体与血管紧张素Ⅱ、血管紧张素Ⅱ1型受体和2型受体的相关性分析用直线相关分析法。结果HE染色和M asson染色结果发现动脉粥样硬化组大鼠主动脉内粥样硬化斑块形成。动脉粥样硬化组大鼠主动脉血管紧张素Ⅱ水平较对照组明显升高(210.80±31.56 ng/L比121.26±25.32 ng/L,P<0.01)。与对照组比较,动脉粥样硬化组主动脉B族Ⅰ型清道夫受体(0.83±0.19比0.16±0.03)、血管紧张素Ⅱ1型受体(1.02±0.12比0.48±0.11)和2型受体(0.97±0.24比0.13±0.03)的蛋白表达明显升高(均P<0.01),且均主要存在于胞膜和胞浆中。动脉粥样硬化组主动脉B族Ⅰ型清道夫受体(0.76±0.17比0.16±0.04)、血管紧张素Ⅱ1型受体(0.83±0.20比0.33±0.08)和2型受体(0.78±0.13比0.12±0.03)的mRNA表达较对照组明显升高(均P<0.01)。动脉粥样硬化组的B族Ⅰ型清道夫受体蛋白表达与血管紧张素Ⅱ水平及血管紧张素Ⅱ1型受体表达呈显著正相关(r=0.717和r=0.711)。结论动脉粥样硬化大鼠主动脉B族Ⅰ型清道夫受体、血管紧张素Ⅱ1型受体和2型受体表达升高,且B族Ⅰ型清道夫受体表达的增高与血管紧张素Ⅱ产生增加和血管紧张素Ⅱ1型受体激活有关。

Aim To eluciadate the genesis of atherosclerosis by investigating the level of angiotensinⅡ（AngⅡ）,the expression of scavenger receptor class B type Ⅰ（SR-BⅠ）,angiotensinⅡ receptors type 1（AT1）,type 2（AT2） and the relationships among them. Methods Eighteen rats were randomly divided into two groups as control group and atherosclerosis group.Atherosclerosis group were given high cholesterol feeds,vitamin D3 and aorta balloon injury.At the end of 12 weeks,HE and Masson stain were used to detect the structure of aorta wall and atherosclerotic plaque.The concentration of AngⅡ was detected by the method of radio-immunity.The protein expression of SR-BⅠ,AT1 and AT2 were investigated by Western Blot and immunohistochemistry,while their mRNA expression were measured by real time reverse transcription polymerse chain reaction（RT-PCR）.The correlation between variances were analyzed by linear regression analysis. Results In atherosclerosis group,some endothelial cells were lost and the intima thicked.The smooth muscle cell（SMC） proliferated and lined up in disorder.The smooth muscles in the media were atrophic slightly.The structures and arrangements of elastic fibers were in disorder and the fibrous tissues proliferated.There were some hyperplasy in the aortic wall and formed atherosclerotic plaques contained with hyperplastic fibers.All of these were observed by HE and Masson stain.The level of AngⅡ in atherosclerosis group was higher than that in control group（210.80±31.56 ng/L vs 121.26 ± 25.32 ng/L,P〈0.01）.Compared with control group,the protein expression of SR-BⅠ,AT1 and AT2 increased significantly in atherosclerosis group（0.83±0.19 vs 0.16±0.03,P〈0.01;1.02±0.12 vs 0.48±0.11,P〈0.01;0.97±0.24 vs 0.13±0.03,P〈0.01）,and expressed mainly in cell membrane and cytoplasma.The aorta mRNA expression of SR-BⅠ,AT1 and AT2 increased significantly in atherosclerosis group than that in control group（0.76±0.17 vs 0.16±0.04,P〈0.01;0.83±0.20 vs 0.33±0.08,P〈0.01;0.78±0.13 vs 0.12±0.03,P〈0.01）.The protein expression of SR-BⅠ was directly related to the level of AngⅡ and the expression of AT1（r=0.717,P〈0.05 and r=0.711,P〈0.05）. Conclusion The expression of aortic SR-BⅠ,AT1 and AT2 increase significantly in atherosclerotic rats,furthermore the increased expression of SR-BⅠ is related to the elevation of AngⅡ and activation of AT1.