左旋精氨酸对模拟缺血再灌注乳兔培养窦房结细胞损伤的保护作用

目的 观察模拟缺血再灌注(IR)培养乳兔窦房结细胞(SANC)损伤及左旋精氨酸(L-Arg)的保护作用.方法 对SANC模拟低糖缺氧培养,添加L-Arg和L-Arg 加 L-NAME(L-Arg抑制剂)与培养细胞共同孵育,吖啶橙(AO)标记细胞凋亡,检测细胞内过氧化物歧化酶(SOD)活性、丙二醛(MDA)、总一氧化氮合酶(NOS)、氧化亚氮(NO)水平.细胞分为正常对照组、I120R120 组、I120R120加L-Arg组、I120R120加L-Arg加L-NAME组4组.结果 凋亡细胞体积明显缩小,核呈黄绿色,断裂为多个碎块状,由膜包裹着凸起于细胞表面呈黄绿色凋亡小体.与I120R120组凋亡率(5.21±1.59)%]比较,I120R120加L-Arg组凋亡率(8.70±3.10)%]显著降低(P<0.01);I120R120加L-Arg组细胞SOD活性(46 820±14 450) U/g]较I120R120组 (25 030±8 440) U/g]显著上升,而I120R120加L-Arg组MDA(5.55±3.71)mmol/g]、NO(3.65±1.02) U/g]和NOS(3.73±0.24) μmol/L]较I120R120组MDA(8.42±4.21)mmol/g]、NO (4.62±1.20) U/g]和NOS(4.96±0.52) μmol/L]显著下降(Pa<0.05);而I120R120加L-Arg加L-NAME组各指标较I120R120组无显著性差异(Pa>0.05).结论 补充NO合成底物L-Arg能清除自由基,增加SOD活性,增强细胞抗氧化损伤能力,可能是阻断氧自由基所介导的细胞凋亡机制之一.

Protective Effect of L-Arginine on Simulated Ischemia Reperfusion Injury of Cultured Sinoatrial Node Cell in Neonatal Rabbits

Objective To observe the protective effect of L-Arginine (L-Arg) on simulated ischemia reperfusion (IR) injury of cultured sinoatrial node cell (SANC) in neonatal rabbits.Methods The apoptotic cells were stained with acridine orange(AO) fluorescence and the contents of superoxide(SOD),malondialdehyde(MDA),nitric oxide synthase(NOS),and nitric oxide(NO) of the cultured cells in the different groups were examined.SANC were cultured in hypoglycemic and hypoxic medium to simulate IR injury.Then,L-Arg and L-Arg plus L-nitro-Arginine methyl ester(L-NAME,L-Arg inhibitor) were added in it.SANC were set into 4 groups: control group,I120R120 group,I120R120 plus L-Arg group and I120R120 plus L-Arg plus L-NAME group.Results AO-fluorescence staining showed that the apoptotic cell was dwindled and the nucleus was fractured into many small shivers which were enwrapped and heaved on cell′s surface to become yellow green apoptotic body.The rate of apoptosis was significantly decreased in I120R120 plus L-Arg group (5.21±1.59)%]compared with I120R120 group (8.70±3.10)%](P<0.01);The activity of SOD was increased significantly in I120R120 plus L-Arg group(46 820±14 450)U/g]compared with I120R120group (25 030±8 440)U/g]while the MDA(5.55±3.71)mmol/g],NO(3.65±1.02)μmol/L]and NOS (3.73±0.24)U/g]were significantly decreased in I120R120 plus L-Arg group compared with I120R120group(8.42±4.21)mmol/g,(4.62±1.20)μmol/L,(4.96±0.52)U/g](Pa<0.05).However,there were no significant differences in them between I120R120 plus L-Arg plus L-NAME group and I120R120 group (Pa>0.05).Conclusions The supplement of appropriate amount of L-Arg can clean out and decrease the excrescent oxygen free radicals,improve SOD activity and increase the oxidation resistance of cells,which may be one of the mechanisms interdicting the apoptotic process induced by oxygen free radicals.