白细胞参与心肌细胞再灌注损伤和心肌细胞延迟预适应研究

Anoxia/reoxygenation Injury in Cardiac Myocytes with Respect to Neutrophil and Development of Delayed Preconditioning in Cardiac Myocardial Cells

目的 :为白细胞参与心肌缺血再灌注损伤提供实验依据 ;同时 ,从白细胞趋化作用和心肌细胞内氧自由基角度探讨心肌细胞延迟预适应并进一步阐明其产生机理。方法 :评估正常对照组、缺氧 /复氧组、延迟预适应组和过氧化氢预适应组心肌细胞对白细胞趋化作用、心肌细胞内氧自由基水平和超氧化物歧化酶 (SOD)活性。结果 :与正常对照组比较 ,心肌细胞经过缺氧 /复氧后能吸引更多的白细胞渗过血管内皮细胞 (P <0 .0 5 ) ,且细胞内氧自由基水平显著高于正常对照组心肌细胞 (P <0 .0 5 ) ,SOD水平则无增高。然而 ,经过延迟预适应或过氧化氢预适应的心肌细胞再次缺氧 /复氧后对白细胞趋化作用则明显低于没有预处理的心肌细胞 (P <0 .0 5和P <0 .0 5 ) ,细胞内SOD活性则较后者高 (P <0 .0 1)。结论 :心肌细胞经缺氧 /复氧后能释放趋化因子吸引白细胞 ;经延迟预适应的心肌细胞对缺氧 /复氧的耐受能力提高 ,其产生机制是细胞内SOD合成增加。

Objective:To provide more evidence to the idea of neutrophil's important roles in cardiac myocardium reperfusion injury.And to probe cardiac myocytes,delayed preconditioning to anoxia/reoxygenation(A/R)with respect to their ability to promote neutrophil transendothelial migration and oxidant stress.Methods:Cultured cardiac myocytes were challenged with normoxia/reoxygenation(N/R),A/R,two separated A/R in 24 hours(delayed preconditioning)and once in H 2O 2 followed by another A/R in 24 hours(H 2O 2 preconditioning).Supernatants and myocytes were evaluated for chemotactic activity,oxidant atress(DHR oxidation)and SOD activity respectively.Results:Supernatants from A/R conditioned myoctyes increased neutrophil transendothelial migration,whereas,supernatants from these preconditioned myocytes no longer promoted neutrophil transendothelial migration.The A/R challenge was associated with an increase in oxidative stress,but,the second A/R challenge was not in both A/R and H 2O 2 preconditioned myocytes.SOD activity in N/R and A/R showed no difference,whereas,SOD activity was increased during the second A/R challenge in A/R and H 2O 2 preconditioned myocytes.Conclusions:The findings suggest that cardiac myocytes can produce chemotactic activity to neutrophil after A/R challenge.And cardiac myocytes can develop A/R tolerance with respect to production of a chemotactic factor and that modulation of A/R-induced oxidative stress plays an important role in the development of delayed preconditioning.