【摘要】 目的 探讨Egr3基因敲除对动脉粥样硬化小鼠主动脉组织炎症和血管新生的影响及可能机制。方法16只SPF级Egr3^fl/fl小鼠随机分为对照组和模型组各8只，16只SPF级Egr3^{（fl/fl,Cdh5-cre）}小鼠随机分为Egr3^-/-组和Egr3^-/-+模型组各8只，均为雄性，8周龄，体质量16.2～23.5g。Egr3^-/-组和Egr3^-/-+模型组给予20g/L他莫昔芬溶液1.5mg/d腹腔注射，持续5d以诱导Egr3基因敲除；对照组和模型组给予同体积玉米油腹腔注射。饲养1周后，对照组和Egr3^-/-组常规饲料喂养12周；模型组和Egr3^-/-+模型组经尾静脉注射AAV8-PCSK9 5×10¹¹ vg/mL，再高脂饲料喂养12周以构建动脉粥样硬化模型。造模后检测血糖、总胆固醇（TC）、三酰甘油（TG）、低密度脂蛋白胆固醇（LDL-C）、高密度脂蛋白胆固醇（HDL-C）水平，采用HE染色观察主动脉组织病理情况，采用油红O染色检测主动脉斑块面积百分比，采用ELISA法检测血清白细胞介素（IL）-1β、IL-6及主动脉组织内皮型一氧化氮合酶（eNOS）、内皮素-1（ET-1）水平，采用Western blot法检测主动脉组织Egr3、血管内皮生长因子（VEGF）、VEGF受体2（VEGFR2）蛋白相对表达量。结果 对照组主动脉管腔结构尚可，管壁厚度不均，中膜少量脂质沉积，部分内膜细胞肿胀脱落；模型组主动脉结构紊乱，泡沫细胞增多，部分弹性纤维肿胀，中膜大量脂质沉积，内膜纤维组织增生形成纤维帽；Egr3^-/-组主动脉管腔结构较完整，管壁厚度较均匀，中膜脂质沉积较对照组减少；Egr3^-/-+模型组主动脉结构较完整，中膜脂质沉积、内膜纤维组织增生及泡沫细胞较模型组减少。Egr3^-/-组、对照组、Egr3^-/-+模型组、模型组主动脉斑块面积百分比[（1.13±0.30）%、（4.38±1.12）%、（7.64±0.34）%、（9.32±1.39）%]依次升高（F=61.662,P<0.001）。4组血糖、TC、TG、LDL-C、HDL-C、IL-1β、IL-6及主动脉组织eNOS、ET-1水平和Egr3、VEGF、VEGFR2蛋白相对表达量比较差异均有统计学意义（F=10.651～639.612,P均<0.05）。模型组、Egr3^-/-+模型组血糖、TC、TG、LDL-C、IL-1β、IL-6及主动脉组织ET-1水平、VEGF蛋白相对表达量均高于对照组、Egr3^-/-组（P<0.05），模型组均高于Egr3^-/-+模型组（P<0.05）；模型组、Egr3^-/-+模型组HDL-C水平低于对照组、Egr3^-/-组（P<0.05）；模型组、Egr3^-/-+模型组主动脉组织eNOS水平低于对照组、Egr3^-/-组（P<0.05），模型组低于Egr3^-/-+模型组（P<0.05）;Egr3^-/-组、Egr3^-/-+模型组、对照组、模型组主动脉组织Egr3蛋白相对表达量依次升高（P<0.05）；模型组主动脉组织VEGFR2蛋白相对表达量高于对照组、Egr3^-/-组、Egr3^-/-+模型组（P<0.05）。结论 动脉粥样硬化小鼠Egr3表达上调，Egr3基因敲除可减轻小鼠动脉粥样硬化病变，可能与抑制主动脉组织炎症和血管新生有关。更多还原

【Abstract】 Objective To explore the effects of Egr3 gene knockout on aortic inflammation and angiogenesis of atherosclerotic mice and its potential mechanism.Methods Sixteen SPF-grade Egr3^fl/fl mice were randomly divided into a control and model groups（8 each）,and 16 SPF-grade Egr3^{（fl/fl,Cdh5-cre）}mice were randomly divided into an Egr3^-/-and Egr3^-/-+model groups（8 each）.All were 8-week-old male mice,with body mass of 16.2 to 23.5g.The Egr3^-/-and Egr3^-/-+model groups received intraperitoneal injection of tamoxifen solution（20 g/L,1.5 mg/d）for 5 consecutive days to induce Egr3 knockout,and the control and model groups received intraperitoneal injection of equal volume of corn oil.After 1-week feeding,the control and Egr3^-/-groups were fed regular chow for 12 weeks;the model and Egr3^-/-+model groups were injected with AAV8-PCSK9(5×10¹¹ vg/mL)via tail vein,followed by high-fat diet feeding for 12 weeks to establish the atherosclerotic model.After modeling,the levels of blood glucose,total cholesterol（TC）,triglyceride（TG）,low-density lipoprotein cholesterol（LDL-C）,and high-density lipoprotein cholesterol（HDL-C）were measured.Aortic histopathological changes were observed with HE staining;aortic plaque area percentage was detected with Oil Red O staining.Serum interleukin（IL）-1βand IL-6 levels,as well as aortic endothelial nitric oxide synthase（eNOS）and endothelin-1（ET-1）levels were measured with ELISA.The relative expressions of Egr3,vascular endothelial growth factor（VEGF）,and VEGF receptor 2（VEGFR2）proteins in aortic tissue were detected with Western blot.Results The control group exhibited relatively preserved aortic luminal structure with uneven wall thickness,minimal lipid deposition in the media,and partial intimal cell swelling and detachment.The model group displayed disorganized aortic architecture,increased foam cells,swollen elastic fibers,massive medial lipid deposition,and intimal fibrous tissue proliferation forming fibrous caps.The Egr3^-/-group demonstrated relatively intact luminal structure with uniform wall thickness and reduced medial lipid deposition compared with the control group.The Egr3^-/-+model group showed relatively intact aortic structure with decreased medial lipid deposition,intimal fibrous proliferation,and foam cells compared with the model group.The percentage of aortic plaque area progressively increased across the Egr3^-/-,control,Egr3^-/-+model,and model groups[（1.13±0.30）%,（4.38±1.12）%,（7.64±0.34）%,（9.32±1.39）%]respectively（F=61.662,P<0.001）.Significant differences were observed among the four groups in the levels of blood glucose,TC,TG,LDL-C,HDL-C,IL-1β,IL-6,eNOS and ET-1,as well as relative expressions of Egr3,VEGF and VEGFR2 proteins（F=10.651-639.612,all P<0.05）.The levels of blood glucose,TC,TG,LDL-C,IL-1β,IL-6 and ET-1,as well as relative expression of VEGF protein were higher in the model and Egr3^-/-+model groups than those in the control and Egr3^-/-groups（P<0.05）,and higher in the model group than those in the Egr3^-/-+model group（P<0.05）.The HDL-C level was lower in the model and Egr3^-/-+model groups than that in the control and Egr3^-/-groups（P<0.05）.The eNOS level was lower in the model and Egr3^-/-+model groups than that in the control and Egr3^-/-groups（P<0.05）,and in the model group than that in the Egr3^-/-+model group（P<0.05）.The Egr3 protein expression progressively increased across the Egr3^-/-,Egr3^-/-+model,control,and model groups（P<0.05）.The model group exhibited higher VEGFR2 protein expression than the control,Egr3^-/-,and Egr3^-/-+model groups（P<0.05）.Conclusion Egr3 expression is upregulated in atherosclerotic mice,and Egr3 knockout attenuates atherosclerotic lesions,possibly by inhibiting aortic inflammation and angiogenesis.更多还原