丹蒌片对大鼠心肌缺血再灌注损伤的保护作用及机制

目的:观察丹蒌片对大鼠心肌缺血再灌注损伤(MIRI)的保护作用,并探讨其机制。方法:将80只健康成年雄性Wistar大鼠随机分为假手术组(以0.5%羧甲基纤维素钠溶液10 m L·kg~(-1)灌胃)、模型组(以0.5%羧甲基纤维素钠溶液10m L·kg~(-1)灌胃)、丹蒌片组(0.9 g·kg~(-1))。预防性给药7 d后,结扎大鼠心脏冠脉左前降支,50 min后复灌,制作大鼠心肌缺血再灌注损伤模型。每组取6只大鼠于复灌2 h检测血清乳酸脱氢酶(LDH),肌酸激酶同工酶(CK-MB),内皮素(ET),一氧化氮(NO)水平及心肌组织丙二醛(MDA)及髓过氧化物酶(MPO)水平。剩余大鼠于造模前及复灌48 h进行心脏射血分数检测,每组取6只进行原位末端转移酶标记技术(TUNEL)染色评估心肌细胞凋亡指数,蛋白免疫印迹法(Western blot)检测心肌含半胱氨酸的天冬氨酸蛋白水解酶(Caspase)-3,B细胞淋巴瘤-2(Bcl-2)及Bcl-2相关X蛋白(Bax)蛋白表达。余大鼠行依文思蓝-TTC染色评估心肌梗死面积。结果:复灌2 h时,与模型组比较,丹蒌片组血清LDH及CK-MB均明显降低(P0.05),血清ET-1明显降低,NO明显升高(P0.05),心肌组织MDA及MPO明显升高(P0.05)。复灌48 h时,与模型组比较,丹蒌片组心脏EF值明显上升(P0.05),心肌梗死范围明显下降(P0.05),心肌凋亡指数明显下降(P0.01);与模型组比较,丹蒌片组心肌Caspase-3,Bax蛋白表达明显升高(P0.05,P0.01),Bcl-2蛋白表达下降(P0.05)。结论:丹蒌片在MIRI早期可以保护内皮细胞功能、抑制氧化及炎症浸润,在MIRI晚期可能通过抑制细胞凋亡,缩小心肌梗死面积,改善心功能来实现对心脏的保护作用。

Protective Effect and Mechanism of Danlou Tablets on Myocardial Ischemia Reperfusion Injury in Rats

Objective: To explore the protective effect and mechanism of Danlou tablets (DT) on myocardial ischemia reperfusion injury (MIRI) in rats. Method: The 80 male healthy Wistar rats with body weight of (300±20) g were randomly divided into sham operation group, model group and Danlou tablets group. Rats in sham operation group and model group were administered with 0.5%CMC-Na solution at the daily dose of 10 mL·kg^-1 by ig, and rats in the DT group were administered with 0.9 g·kg^-1 Danlou tablets. After prophylactic administration for 7 days, the left anterior descending branch of the rats heart were ligatured for 50 minutes to create the models of myocardial ischemia reperfusion injury in rats. The levels of lactate dehydrogenase (LDH), creatine kinase isoenzyme (CK-MB), endothelin (ET) and nitric oxide (NO) in serum, and malondialdehyde (MDA) and myeloperoxidase (MPO) in myocardial tissues were detected after 2 h reperfusion in 6 rats of each group. Ultrasound was used to observe the cardiac ejection fraction (EF) before and after 48 h reperfusion. The 6 rats in each group were selected for TdT-mediated dUTP nick end labeling(TUNEL) staining to assess the apoptosis index of myocardial cells, and then the protein expression levels of Caspase-3, Bax and Bcl-2 protein in cardiac muscle tissues were detected by Western blot. Evans blue-TTC staining was used to assess the myocardial infarction area in the remaining rats. Result: After reperfusion for 2 h, as compared with model group, the levels of serum LDH, CK-MB and ET-1 in DT group were significantly reduced (P<0.05), while the levels of NO, MDA and MPO were significantly elevated (P<0.05). After reperfusion for 48 h, as compared with model group, the EF values in Danlou tablets group were significantly elevated (P<0.05), with obvious decreases in the myocardial infarction size and myocardial apoptosis index (P<0.05), myocardial Caspase-3 and Bax protein expression levels in Danlou tablets group were significantly increased (P < 0.05, P < 0.01), and Bcl-2 protein expression levels were decreased (P<0.05). Conclusion: Danlou tablets can protect endothelial cells, inhibit oxidative and inflammatory infiltration in the early stage of MIRI. The protective effect on myocardial ischemia reperfusion injury in rats of Danlou tablets may be related to inhibiting apoptosis, reducing myocardial infarct size and improving cardiac function in the late stage of MIRI.