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目的探讨使用增强型体外反搏器(EECP)提高血流剪切应力对高胆固醇血症实验猪血管病理形态、血管内皮形态与功能及核因子κB(NFκB)表达的影响。方法健康雄性家猪随机分为普通饲料组、高脂对照组、高脂反搏组。后两组同量持续高胆固醇饲料喂养建立高胆固醇血症及早期动脉粥样硬化动物模型。高脂反搏组在高胆固醇喂养2个月后进行体外反搏。15周后取出冠状动脉、胸主动脉和腹主动脉行病理形态学观察和NFκB免疫荧光激光共聚焦扫描。结果高脂对照组及高脂反搏组血脂水平较普通饲料组显著升高(P<0.01),而高脂对照组与高脂反搏组之间血脂水平差异无统计学意义(P>0.05)。主动脉大体苏丹Ⅲ染色示高胆固醇血症猪斑块形成较普通饲料组增多;而高脂反搏组斑块/内膜面积比[(3.33±2.40)%]显著少于高脂对照组[(12.03±7.12)%](P<0.05)。扫描电镜示高脂对照组内皮细胞排列紊乱,大量破坏脱落,有较多血小板黏附;高脂反搏组内皮细胞较完整,沿血流方向梭形排列,血小板黏附较少。透射电镜示高脂对照组内皮细胞变性凋亡脱落显著,内皮下大量泡沫细胞积聚,平滑肌细胞呈合成型改变,大量增生并向内膜移行;而高脂反搏组上述改变明显减轻。冠状动脉HE染色及弹力纤维染色示高脂对照组弹力纤维紊乱断裂,内膜较普通饲料组增厚[(24.36±9.72)μm比(9.97±4.02)μm,P<0.05];而高脂反搏组的内膜增厚比高脂对照组明显减少[(11.87±5.95)μm比(24.36±9.72)μm;P<0.05]。免疫荧光激光共聚焦扫描示高胆固醇血症猪冠脉内皮细胞及平滑肌细胞的细胞核NFκB荧光强度较普通饲料组增高,但高脂反搏组荧光强度较高脂对照组减少(P<0.05)。结论通过体外反搏提高血流剪切应力可改善血管内皮细胞形态与功能,减轻内膜增生和血管重塑,从而抑制高胆固醇血症猪早期动脉粥样硬化的形成和进展。其机制可能与下调NFκB的活性表达有关。
Objective To investigate the effects of enhanced ex vivo pump (EECP) on the vascular morphology, the morphology and function of vascular endothelial cells and the expression of nuclear factor κB (NFκB) in experimental hypercholesterolemic piglets. Methods Healthy male domestic pigs were randomly divided into normal feed group, high fat control group and high fat counterpulsation group. After two groups of the same amount of sustained high cholesterol feed to establish hypercholesterolemia and early atherosclerosis animal model. High-fat counterpulsation group in high cholesterol feeding two months after counter-stroke in vitro. After 15 weeks, the coronary arteries, thoracic aorta and abdominal aorta were removed for histopathological observation and NFκB immunofluorescence confocal laser scanning. Results Compared with normal diet group, the level of serum lipids in high-fat control group and high-fat counterpulsation group was significantly increased (P <0.01), but there was no significant difference between high-fat control group and high-fat counterpulsation group ). Aorta gross Sudan Ⅲ staining showed hypercholesterolemia pig plaque formation than the normal feed group increased; and high fat diet group plaque / intimal area ratio [(3.33 ± 2.40)%] was significantly less than the high-fat control group [ (12.03 ± 7.12)%] (P <0.05). Scanning electron microscopy showed that the endothelial cells in the hyperlipidemic control group were disordered, a large number of damaged and shedded, and more platelets adhered. The endothelial cells in the high-fat counterpulsation group were more complete and arranged in a fusiform pattern along the blood flow with less platelet adhesion. Transmission electron microscopy showed that the degeneration and apoptosis of endothelial cells in the hyperlipidemic control group shed off significantly, a large number of foam cells accumulated in the endothelium, the smooth muscle cells showed a synthetic change, a large number of hyperplasia and intimal migration; Coronary artery HE staining and elastic fiber staining showed that the hyperlipidemic control group had disorganized elastic fibers, which were thicker than the normal group ([(24.36 ± 9.72) μm vs (9.97 ± 4.02) μm, P <0.05] The intimal thickening in stroke group was significantly lower than that in high-fat control group [(11.87 ± 5.95) μm vs (24.36 ± 9.72) μm; P <0.05]. Immunofluorescent confocal laser scanning showed hypercholesterolemia in pig coronary endothelial cells and smooth muscle cells nuclear NFκB fluorescence intensity increased compared with the normal diet group, but the fluorescence intensity of high-fat group was lower than the control group (P <0.05). Conclusions Increased shear flow stress through extracorporeal counterpulsation can improve the morphology and function of vascular endothelial cells, reduce intimal hyperplasia and vascular remodeling, and thus inhibit the formation and progression of early atherosclerosis in hypercholesterolemic pigs. The mechanism may be related to the down-regulation of NFκB expression.