oxLDL对转人apoAI基因小鼠动脉平滑肌细胞胆固醇摄取和清除的影响  

Effect of oxLDL on the Uptake and Clearance Rate of Cholesterol in Vascular Smooth Muscle Cells Originated from Human apoAI Transgenic Mice

作　　者：曾莹[1] 赵高峰[1] 钱军[1] 王宗立[1] 佘铭鹏[1] 

机构地区：[1]中国医学科学院 中国协和医科大学 基础医学研究所病理研究室,北京100005

出　　处：《中国医学科学院学报》2001年第4期328-332,共5页Acta Academiae Medicinae Sinicae

基　　金：国家科委攀登计划(1997~2000)资助

摘　　要：目的 明确氧化低密度脂蛋白（oxLDL）对转人apoAI基因 C57BL/6小鼠主动脉平滑肌细胞（tr-SMC）胆固醇清除与摄取的影响；转入的apoAI基因是否有助于减轻oxLDL引起的SMC胆固醇积聚和对细胞的损害；以及oxLDL的刺激，对细胞已转入的apoAI基因表达的影响。方法 用已建立的含小鼠金属硫蛋白I（MT-I）启动子的人apoAI转基因C57BL/6 小鼠主动脉SMC，通过3H-胆固醇标记率和清除率测定，观察oxLDL对tr-SMC胆固醇摄取与清除的影响。通过RT-PCR及 Northern blot技术检测oxLDL对tr-SMC基因表达的影响。结果 30 μg／ml oxLDL明显促进小鼠SMC增生；未见tr-SMC与非转基因小鼠平滑肌细胞（n-SMC）在标记率间的差别，oxLDL刺激后标记率增加约100%；tr-SMC较n-SMC细胞内胆固醇清除率增加40% ～ 50%。oxLDL刺激后，n-SMC清除率下降28%，而 tr-SMC仅下降10%。RT-PCR 及Northern blot表明oxLDL刺激后tr-SMC 的h-apoAI基因表达明显增加。结论 转人apoAI 基因小鼠SMC的基因表达有助于减轻oxLDL引起的SMC胆固醇积聚；oxLDL的刺激促进tr-SMC 的人apo AI基因表达，表达的 h-apo AI可抑制oxLDL对平滑肌细胞的损害。Objective Study on(1)inhibition of oxidized low density lipoprotein(oxLDL)effect on the upt- ake and clearance of intra-cellular 3H-cholesterol in vascular smooth muscle cells(v-SMC)originated from the human-apoAI transgenic mice(C57BL/6)；(2)change of human-apolipoprotein AI(h-apoAI)mRNA expression in v-SMC after oxLDL stimulation and the protective effect of expressed h-apoAI on v-SMC against oxLDL intoxication． Methods (1)v-SMC isolated from human apoAI transgenic mice possessing a recombined gene connected beforehand with a mouse metallothionein-I(MT-I)as the pro- moter；(2)study of h-apoAI mRNA expression from v-SMC of the transgenic mice by RT-PCR and Northern blot． Results oxLDL(30 μg/ml) strongly promoted v-SMC proliferation． No difference found on 3H-cholesterol uptake between smooth muscle from normal mouse aorta(n-SMC)and smooth muscle cells from transgenic mouse aorta(tr-SMC) of the control groups, the uptake rates of both kinds of SMC rose 100% after oxLDL stimulation． The efflux rates of 3H-cholesterol in tr-SMC were much higher than those of n-SMC(40%～ 50%)． After oxLDL stimulation, the clearance rates fell by 28% and 10% respectively for n-SMC and tr-SMC． The result of RT-PCR and Northern blot showed a marked increase of h-apoAI gene expression after oxLDL stimulation Conclusions Expression of h-apoAI gene in C57BL/6 mice enables to decrease the accumulation of cholesterol in v-SMC． tr-SMC are capable to alleviate the harmful effect of oxLDL on v-SMC due to the increase of h-apoAI expression．

关 键 词：氧化低密度脂蛋白 载脂蛋白AI 转基因 平滑肌细胞 胆固醇 动脉血管 

分 类 号：Q513.5[生物学—生物化学] Q463