原儿茶酸通过eNOS-NO-cGMP通路改善ApoE-/-小鼠血管内皮舒张功能

PROTOCATECHUIC ACID IMPROVES VASCULAR ENDOTHELIAL DILATATION VIA eNOS-NO-cGMP PATHWAY IN ApoE-DEFICIENT MICE

目的探讨原儿茶酸(PCA)对ApoE基因敲除小鼠(ApoE-/-)血管内皮舒张功能的影响及可能机制。方法45只雄性ApoE-/-小鼠随机分为3组:对照组喂养普通AIN-93G饲料(Con组)、低剂量PCA组(0.0003%w/w,L-PCA组)、高剂量PCA组(0.003%w/w,H-PCA组),干预4 w后观察小鼠胸主动脉舒张功能、eNOS及其磷酸化(phos-eNOSser1177)蛋白水平、cGMP和NO的水平。另外,采用氧化型低密度脂蛋白(ox-LDL)造成原代小鼠主动脉内皮细胞(MAECs)损伤模型,评价PCA对细胞eNOS及其磷酸化(phos-eNOSser1177)蛋白水平和NO水平的影响。结果H-PCA组小鼠动脉舒张功能、phos-eNOSser1177表达、cGMP和NO水平分别显著高于对照组和L-PCA组;加入内皮型一氧化氮合酶抑制剂(L-NAME)或鸟苷酸环化酶抑制剂(ODQ)后,PCA对小鼠动脉血管舒张功能保护作用下降。细胞实验结果显示PCA对eNOS蛋白表达和NO无影响,但显著提高phos-eNOSser1177的水平。结论原儿茶酸可以改善血管内皮舒张功能,其机制可能与激活eNOS-NO-cGMP通路有关。

Objective To investigate the effect ofprotocatechuic acid （PCA） on thoracic aorta endothelial function in apolipoprotein E-deficient （ApoE-/-） mice. Methods Forty-five male ApoE-/- mice were randomly divided into three groups： control group （AIN-93G diet, Con）, low dosage PCA group （0.0003 % w/w, L-PCA） and high dosage PCA group （0.003 % w/w, H-PCA）. The thoracic aorta endothelial vasodilatation, eNOS and phos-eNOSser1177, cGMP and NO levels were measured after 4 w treatment. In addition, the effects of PCA on eNOS, phos-eNOSser 177, and NO levels were evaluated in ox-LDL-exposed primary murine aortic endothelial cells （MAECs） culture. Results The endothelial vasodilatation and the levels of phos-eNOS177, cGMP and NO of thoracic aorta in H-PCA group were significantly higher than those in control group and L-PCA group. The protective effect of PCA on aortic endothelial vasodilatation was blocked after adding the eNOS inhibitor L-NAME, or GC inhibitor ODQ. PCA significantly increased phos-eNOS^erllT7 expression without obvious effects on total eNOS expression and cellular NO level. Conclusion PCA could improve the vascular endothelial function at least in part, via activating the eNOS-NO-cGMP pathway.