金属硫蛋白和瑞舒伐他汀对小鼠动脉粥样硬化和SM22α表达的影响

Effect of Metallothionein and Rosuvastatin on Atherosclerosis and SM22α Expression in ApoE-deficient Mice

目的 探讨金属硫蛋白（MT）和HMG-CoA还原酶抑制剂瑞舒伐他汀对ApoE基因缺陷小鼠动脉粥样硬化以及血管平滑肌22α蛋白（SM22α）表达的影响.方法 30只6周龄雄性ApoE基因缺陷小鼠随机分为高脂模型组、瑞舒伐他汀组、金属硫蛋白组,高脂饮食喂养13周;10只背景品系雄性C57BL/6J小鼠作为正常对照组,正常饮食喂养13周.13周后,摘眼球取血测定血浆总胆固醇（TCH）、甘油三酯（TG）、低密度脂蛋白（LDL-C）的水平,处死小鼠后取主动脉,剪取主动脉弓部位5 mm长主动脉用10％甲醛固定,石蜡包埋,切片,HE染色及SM22α免疫组织化学染色;其余标本-80℃保存,取100 mg主动脉组织两份,分别提取总蛋白和RNA,并做WesternBlot和RT-PCR检测,观察主动脉血管壁形态学变化,定性和定量分析主动脉组织SM22α表达强度变化.结果 与高脂模型组比较,瑞舒伐他汀组血清中TCH、TG、LDL-C水平显著降低（P＜0.05）;金属硫蛋白组与高脂高脂模型组比较,TCH、TG、LDL-C水平无统计学差异（P＞0.05）;和正常对照组相比,高脂模型组主动脉粥样硬化病变程度明显加重,免疫组织化学、Western Blot和RT-PCR方法分析主动脉SM22α蛋白和mRNA的表达均明显减少;金属硫蛋白和瑞舒伐他汀组主动脉粥样硬化病变程度减轻,SM22α蛋白和mRNA的表达均增加.结论 金属硫蛋白对血脂无明显影响,瑞舒伐他汀降低血脂作用明显;ApoE基因缺陷小鼠主动脉组织动脉粥样硬化明显且SM22α表达减少,金属硫蛋白和瑞舒伐他汀可减轻主动脉粥样硬化病变程度并可增加主动脉SM22α的表达.

Objective To research the effect of metallothionein（MT） and rosuvastatin on atherosclerosis and smooth muscle 22 alpha （SM22α） expression in ApoE-deficient mice.Methods Thirty 6-week-old ApoE-deficient male mice were divided into hyperlipidemia model group,rosuvastatin group,and MT group randomly,fed with fatty diet for 13 weeks.Ten background strain C57BL/6J （wild type） male mice were selected as normal control group,and fed with normal diet for 13 weeks.After 13 weeks,eyeballs were extracted and blood was taken from ApoE-deficient mice for detecting lipid profile,then the mice were executed and the aortas were dissociated,5 mm vessel in aorta arch were taken and fixed in 10％ formalin,then treated with paraffin imbedding,slicing,HE staining and SM22α immunohistochemistry staining; some specimen was preserved in-80 ℃ refrigerator,total protein and RNA were extracted,West Blot and RTPCR were taken.To observe morphology changes of aortic wail,to analyse SM22α expression intensity of aorta tissue qualitatively and quantitively.Results The blood lipid level in rosuvastation group was lower than that in hyperlipidemia model group （P＜0.05）.There is no difference in the blood lipid level between MT group and hyperlipidemia model group （P＞0.05）.Compared with normal control group,intimal thickness,plaque volume increased and SM22α protein and mRNA expression decreased in hyperlipidemia model group.Compared with hyperlipidemia model group,intimal thickness,plaque volume decreased and SM22αprotein and mRNA expression increased in MT and rovustatin group.Conclusion The MT has no effect on lipid profile,rovustatin can lower blood lipid obviously.MT and rovustatin can alleviate atherosclerosis lesions and increase SM22α protein and mRNA expression in aorta of ApoE-deficient mice.Their antiathrosclerosis effect is related to up regulating SM22α expression.