一氧化氮参与预处理心肌细胞早期保护作用

目的　明确一氧化氮 (NO)是否诱导预处理心肌细胞早期保护作用。方法　取体外培养的新生大鼠心肌细胞 ,分为如下各组 :①阴性对照组 (Normal组 ) ;②SNAP(5 0 0 μmol·L-1)预处理组 (NO组 ) ;③缺氧预处理组 (HP组 ) ;④NO合成抑制剂L NAME作用细胞后再行缺氧预处理组 (L NAME +HP组 ) ;⑤L 精氨酸 (L Arg)预处理心肌细胞组(L Arg组 ) ;⑥L NAME与L Arg共同作用于心肌细胞组(L NAME +L Arg组 ) ;⑦缺氧复氧损伤组 (H/R组 )。②～⑥组细胞在给予干预因素后使细胞经历 6h缺氧及 3h复氧 ,阳性对照组不予任何处理直接使其缺氧 6h复氧 3h。分别检测心肌细胞存活率及乳酸脱氢酶 (LDH)活性 ,以判定心肌细胞损伤程度。结果　NO预处理心肌细胞后使其缺氧复氧损伤减轻 ,表现为与单纯缺氧复氧组细胞比较其培养上清LDH活性降低 ,细胞存活率提高 (P <0 0 1) ;缺氧预处理和L Arg预处理细胞均可减轻心肌细胞缺氧复氧损伤 (P<0 0 1) ,但此作用可被NOS抑制剂L NAME所拮抗。结论　内源性及外源性NO均可诱导心肌细胞预处理早期保护作用

Nitric oxide preconditioning induced early protection of cardiomyocytes

AIM To study whether nitric oxide preconditioning induce early protection of neonatal rat cardiomyocytes. METHODS Cultured neonatal rat cardiomyocytes were divided into 6 groups. ①Normal group;②NO group: SNAP(500 μmol·L -1 ) was added to cell medium 1 h before lethal hypoxia/reoxygenation (HR) injury (6 h hypoxia and 3 h reoxygenation); ③HP group: Cells were cultured for 60min hypoxia followed by 30 min reoxygenation to form hypoxia preconditioning before lethal HR injury;④ L NAME+HP group: Nitric oxide synthase antagonist L NAME was added during HP stage;⑤ L Arg group: L arginine was added to cell medium 1h before lethal HR injury;⑥ L NAME+ L Arg group: Both L NAME and L Arg were added to cell medium 1 h before lethal HR injury;⑦H/R group: Cells underwent lethal HR injury without any treatment. Cardiomyocytes injury was detected by lactate dehydrogenase(LDH) activity and cell viability. RESULTS Nitric oxide preconditioning can protect cardiomyocytes by reducing LDH activity and improving cell viability ( P <0 01). Both HP and L Arg preconditioning can also reduce cardiomyocytes HR injury( P <0 01),but this protective role can be inhibited by L NAME. CONCLUSION Both internal and external NO preconditioning can induce early protection of cardiomyocytes.