过氧化氢对培养心肌细胞损伤作用的研究

The Injured Effect of Hydrogen Peroxide on Cultured Cardiac Myocytes

氧化应激时产生大量的自由基 ,造成心肌细胞的损伤 .过氧化氢 (H2 O2 )是有机体氧化代谢产物 ,同时是一种活性氧 .应用不同浓度的H2 O2 ,分别于不同作用时间 ,动态观察其对心肌细胞的损伤作用 .从实验结果看到 ,低浓度的H2 O2 (<0 1mmol/L)作用 2h ,使心肌细胞产生早期的生物化学的改变 ,如MDA产生堆积和细胞周期时相改变 (G1期细胞增加 ,G2期细胞减少 ) ,此时心肌酶基本无泄漏 ,心肌细胞的死亡率很低 ,HE形态学观察基本无改变 ;随着H2 O2 浓度的增加 (1～ 5mmol/L)和作用时间的延长 ,进一步诱导细胞损伤加剧 ,LDH释放和MDA积累明显升高 ,细胞死亡率也明显增加 ,已具有统计学意义 .同时可观察到其病理形态学的坏死性改变 ;当 10mmol/LH2 O2 作用时 ,细胞大量死亡 ,形态学可见细胞极度收缩、脱落 ,形成大面积的细胞脱失区 .因此 ,H2 O2 作为一种活性氧自由基 ,依其浓度和作用时间不同可造成不同程度的心肌细胞的损伤 .辣根过氧化物酶作为一种自由基清除剂 ,可明显减少H2 O2

Neonatal rat cardiomyocytes were cultured and cytotoxicity in cultured cardiomyocytes was induced by H 2O 2 over a wide concentration range (0 05～50 mmol/L) to assess dynamically the effect of H 2O 2 on cardiomyocytes. The results showed that application of <0 1 mmol/L H 2O 2 to cardiomyocytes caused accumulation of lipid peroxide(MDA) at 24 h , and phase changes of cellular proliferation cycle at 2h, which represented early biochemical changes. Exposure of cardiomyocytes to the increasing concentrations of H 2O 2 (1～5 mmol/L) induced progressively biochemical injury; the levels of LDH and MDA were significantly higher in the cardiomyocytes exposed to H 2O 2 than in control, with concomitant morphologic changes. When exposed to high concentrations (>10 mmol/L), a large number of cardiomyocytes were found dead by MTT assay, and morphologic examination by HE staining showed that cardiomyocytes contracted extremely, forming a large dropping areas of cardiomyocytes, concurrently with the marked increase of membrane permeability which caused LDH substantial leakage from myocytes to H 2O 2. It is proposed that H 2O 2 accumulation can induce cardiomyocyte cytotoxicity in a dose and time dependent manner. Treatment with low concentrations of H 2O 2 causes cardiomyocytes early slight biochemical changes which represent pre apototic injurious features. High concentrations of H 2O 2 can progressively induce lipid peroxidation, which cause the severe damage of the cell membrane. With exposure of cardiomyocytes to H 2O 2, the magnitude of the cytotoxicity is modulated by horseradish peroxidase (HRP). It is suggested that HRP may protect cardiomyocytes against reactive oxygen species.