西洋参茎叶总皂苷减轻大鼠心肌细胞缺氧/复氧损伤机制的研究

Panax quinquefolium saponins attenuate hypoxia /reoxygenation-induced injury in rat cardiomyocytes

目的:探讨西洋参茎叶总皂苷(PQS)减轻大鼠心肌细胞缺氧/复氧(hypoxia/reoxygenation,H/R)损伤的机制是否与抑制钙调神经磷酸酶(CaN)有关。方法:采用乳鼠心肌细胞H/R损伤模型,转染CaN质粒使其过表达或CaN抑制剂FK506干扰其表达,分为正常对照组、缺氧/复氧组、药物预处理组、CaN过表达+药物预处理组、空载pCDB质粒+药物预处理组及CaN抑制剂+药物预处理组,以流式细胞术检测细胞凋亡,按CaN测试盒步骤测定心肌细胞CaN活性,以Western blotting方法检测心肌细胞CaN表达。结果:与对照组相比,CaN过表达组心肌细胞凋亡率增加(P<0.05),与PQS+H/R组比较,FK506组心肌细胞凋亡率、抗凋亡蛋白Bcl-2和促凋亡蛋白Bax表达、CaN活性及蛋白表达无显著差异(P>0.05)。结论:抑制CaN活性可以减轻心肌细胞H/R损伤,但联合应用FK506对H/R心肌细胞的保护作用不比单独应用PQS强,PQS减轻心肌细胞H/R损伤的机制可能与CaN途径无关。

AIM： To investigate the effects of Panax quinquefolium saponins （PQS） and calcineurin （CaN） signal pathway on cardiomyocyte injury induced by myocardial hypoxia/reoxygenation（H/R）. METHODS：Cultured cardiomyocytes isolated from neonatal Sprague-Dawley rats were used to establish the H/R model. The cells were transfected with pCDB-CaN plasmid to overexpress CaN, or exposed to the CaN inhibitor FK506 to interfere the CaN expression. The cardiomyocytes were divided into control group, H/R group, PQS＋H/R group, CaN＋PQS＋H/R group, pCDB＋PQS＋H/R group and FK506＋PQS＋H/R group. The apoptosis was analyzed by flow cytometry. The activity of CaN in the cardiomyocytes was detected. The protein expression of CaN was determined by Western blotting. RESULTS：Compared with control group, the apoptosis of the cardiomyocytes in CaN group was significantly increased. Compared with PQS＋H/R group, the cell apoptosis, the expression of Bcl-2 and Bax, the activity of CaN and its protein expression in FK506 group were not significantly different. CONCLUSION：Inhibition of CaN activity reduces the H/R injury in cardiomyocytes. However, the mechanism of PQS protecting cardiomyocytes from H/R injury may not be associated with the CaN signaling pathway.