论文部分内容阅读
目的探讨细胞膜钠钙交换蛋白(NCX)在心肌缺血预适应及药物诱导预适应中的作用及可能的信号转导途径。方法培养乳鼠心肌细胞随机分为缺血/再灌注组、缺血预适应组、腺苷预处理组、钙调素依赖蛋白激酶Ⅱ(CaMKⅡ)抑制剂KN-93+缺血预适应组、KN-93+腺苷预处理组及对照组。各组乳酸脱氢酶(LDH)漏出量用生化法测定(n=5),钠钙交换蛋白mRNA表达以半定量RT-PCR检测(n=5),NCX活性以液闪仪测定Na+依赖的45Ca2+摄取率表示(n=5)。结果(1)缺血/再灌注组LDH漏出量显著增加(P<0·05),缺血预适应及腺苷预处理组LDH漏出量均显著降低(P<0·05);KN-93预作用后,缺血预适应及腺苷预处理组LDH漏出量均显著增加(P<0·05)。(2)缺血/再灌注组NCX45Ca2+摄取率比对照组高(P<0·005)。缺血预适应及腺苷预处理组较缺血/再灌注时NCX45Ca2+摄取率显著低(P<0·05),且腺苷预处理组NCX45Ca2+摄取率较缺血预适应组更低(P<0·05)。KN-93+缺血预适应组与缺血/再灌注组NCX45Ca2+摄取率差异无统计学意义,KN-93+腺苷预处理组较缺血/再灌注组NCX45Ca2+摄取率低(P<0·05)。(3)缺血/再灌注组NCXmRNA的表达比对照组显著高(P<0·05);缺血预适应及腺苷预处理组NCXmRNA的表达均显著低(P<0·05);KN-93处理后缺血预适应组及腺苷预处理组NCXmRNA的表达水平显著高(P<0·05),且腺苷预处理组NCXmRNA的表达较缺血预适应组更高(P<0·05)。结论缺血预适应及腺苷预处理对心肌的保护作用与细胞膜NCX有关,缺血预适应中NCX对心肌损伤保护作用经CaMKⅡ介导,而在腺苷预处理中NCX对心肌损伤保护作用仅部分经CaMKⅡ介导。
Objective To investigate the role of cell membrane sodium-calcium-exchange protein (NCX) in myocardial ischemic preconditioning and drug-induced preconditioning and possible signal transduction pathways. Methods The neonatal rat cardiomyocytes were randomly divided into ischemia / reperfusion group, ischemia preconditioning group, adenosine preconditioning group, KN-93 + ischemic preconditioning group, CaMKⅡ inhibitor, KN-93 + adenosine preconditioning group and control group. The leakage of lactate dehydrogenase (LDH) in each group was determined by biochemical method (n = 5), the expression of sodium-calcium exchange protein mRNA was detected by semi-quantitative RT-PCR (n = 5) 45Ca2 + uptake rate (n = 5). Results LDH leakage was significantly increased in ischemia / reperfusion group (P <0.05), LDH leakage in ischemic preconditioning group and adenosine preconditioning group were significantly decreased (P <0.05), and KN-93 After preconditioning, LDH leakage of ischemic preconditioning and adenosine preconditioning increased significantly (P <0.05). (2) NCX45Ca2 + uptake rate in ischemia / reperfusion group was higher than that in control group (P <0 · 005). The uptake rate of NCX45Ca2 + in ischemic preconditioning and adenosine preconditioning group was significantly lower than ischemia / reperfusion group (P <0.05), and the uptake rate of NCX45Ca2 + in adenosine preconditioning group was lower than that in ischemic preconditioning group (P < 0 · 05). The uptake rate of NCX45Ca2 + was not significantly different between KN-93 + ischemic preconditioning group and ischemia / reperfusion group, and the uptake rate of NCX45Ca2 + in KN-93 + adenosine preconditioning group was lower than that in ischemia / reperfusion group (P <0 · 05). (3) NCXmRNA expression in ischemia / reperfusion group was significantly higher than that in control group (P <0.05); NCXmRNA expression in ischemic preconditioning and adenosine preconditioning group was significantly lower (P <0.05); KN The expression of NCXmRNA in ischemic preconditioning group and adenosine preconditioning group was significantly higher than that in ischemic preconditioning group (P <0.05), and the expression of NCXmRNA in adenosine preconditioning group was higher than that in ischemic preconditioning group · 05). Conclusions The protective effect of ischemic preconditioning and adenosine preconditioning on myocardial cells is related to the cell membrane NCX. The protective effect of NCX on myocardial injury in ischemic preconditioning is mediated by CaMKⅡ, while the protective effect of NCX on myocardial injury in adenosine preconditioning is only Part of CaMK Ⅱ mediated.