柚皮素对缺血再灌注损伤心肌保护作用的机制研究

目的探讨柚皮素(NAR)对心肌缺血再灌注(MI/R)损伤的保护作用及其作用机制。方法通过结扎左冠脉前降支30 min,再灌注120 min,建立MI/R大鼠模型,随机分为NAR高、中、低剂量组(100、50、25 mg/kg),假手术组,模型组,各10只。各组于术前1周开始腹腔注射给药,1次/d。再灌注后取血清,采用比色法测定肌酸激酶(CK)和乳酸脱氢酶(LDH)活性,ELISA法测定肿瘤坏死因子-α(TNF-α)和白介素-1β(IL-1β)水平;取心脏,染色法测定心肌梗死面积;取心肌匀浆,测定髓过氧化物酶(M PO)活力。结果 NAR高剂量组可使心肌梗死面积缩小至32.91%,与模型组(39.78%)比较差异有统计学意义(P<0.05);NAR各剂量组血清CK、LDH活性均降低,与模型组比较差异有统计学意义(P<0.05或P<0.01);NAR各剂量组心肌MPO活力均明显降低(P<0.05或P<0.01);NAR高、中剂量均可降低血清TNF-α和IL-1β水平(P<0.05或P<0.01),低剂量亦可降低血清IL-1β水平(P<0.05)。结论 NAR预处理可保护MI/R所致心肌损伤,其机制与抑制中性粒细胞浸润、减少炎性细胞因子的释放等有关。

Protective mechanisms of naringenin against myocardial ischemia/reperfusion inju-ry

Objective To investigate the protective mechanisms of naringenin ( NAR)against myocardial is-chemia/reperfusion( MI/R)injury. Methods Rat model of MI/R injury was established by coronary artery ligation for 30 min followed by 120 min reperfusion. Then rats were divided randomly into 5 groups( n=10 ):sham group, model group and NAR groups(100,50 and 25 mg/kg). NAR was administered by intraperitoneal injection once daily for 7 d before operation. The activities of CK and LDH and levels of TNF-α and IL-1β were examined by colorimetric and ELISA method respectively after reperfusion. The area of myocardial infarction was calculated and MPO activity in heart homogenate was detected. Results High dose of NAR significantly reduced the area of myocardial infarction to 32. 91%,which was better than that of model group( 39. 78%). The activities of CK and LDH in NAR groups were lower than those of model group( P﹤0. 05 or P﹤0. 01 ). NAR evidently reduced the MPO activity in heart homoge-nate(P﹤0. 05 or P﹤0. 01). The levels of TNF-α and IL-1β in NAR groups(100,50 mg/kg)were lower than those of model group( P﹤0. 05 or P﹤0. 01 ),and 25 mg/kg of NAR inhibited the IL-1β level in serum too( P﹤0. 05 ). Conclusion The effect of NAR pretreatment on MI/R injury appears to be associated with the inhibition of neutrophil infiltration and expression of inflammatory cytokines.