蛋白激酶C抑制剂Ro-31-8220逆转高糖诱导乳鼠心肌细胞肥大的作用及其相关机制

目的： 观察蛋白激酶C（PKC）抑制剂Ro-31-8220对高糖诱导的乳鼠心肌细胞肥大的影响，并初步探讨PKC及其下游信号转导途径在其中的作用机制。方法：建立乳鼠心肌细胞培养模型，随机分成对照组（5.5 mmol·L-1）、不同浓度高糖组（10 mmol·L-1、15 mmol·L-1、20 mmol·L-1、25.5 mmol·L-1）、高糖（25.5 mmol·L-1）+PKC抑制剂Ro-31-8220组（50 nmol·L-1）和高糖（25.5 mmol·L-1）+NF-κB抑制剂BAY11-7082（5 mmol·L-1）组，分别测定各组乳鼠心肌细胞直径和蛋白质含量，并应用Western blotting检测乳鼠心肌细胞PKC-α、PKC-β2、p-PKC-α、p-PKC-β2、NF-κB和c-Fos等蛋白的表达水平。结果：高糖可以明显诱导乳鼠心肌细胞肥大，提高乳鼠心肌细胞PKC-α、PKC-β2、p-PKC-α、p-PKC-β2、NF-κB和c-Fos的蛋白表达，与对照组相比差异显著（P<0.01），并呈现一定的浓度依赖性；而Ro-31-8220能够逆转上述现象，其细胞直径和蛋白表达低于高糖组，并有显著差异（P<0.01）。结论：高糖能够浓度依赖性地诱导心肌细胞肥大，而PKC抑制剂Ro-31-8220则能抑制高糖所诱导的这种反应，其机制可能与PKC/NF-κB/c-Fos途径相关。

Reverse effect of protein kinase C inhibitor Ro-31-8220 on the hypertrophy of cardiomyocytes of neonatal rats induced by high glucose levels

AIM: To study the effect of protein kinase C (PKC) inhibitor Ro-31-8220 on the hypertrophy of cardiomyocytes of neonatal rats induced by high glucose levels, and to investigate the role of PKC and its downstream signal transduction pathway. METHODS: Using cultured neonatal cardiac myocytes as a model, the cells were divided into: (1) control group (glucose 5.5 mmol/L); (2) different high glucose level (10 mmol/L,15 mmol/L, 20 mmol/L, 25.5 mmol/L); (3) high glucose level (25.5 mmol/L) + PKC inhibitor Ro-31-8220 (50 nmol/L); (4) high glucose level (25.5mmol/L) + NF-κB inhibitor (BAY11-7082, 5 mmol/L). The cellular diameters and protein level were measured and the expression of PKC-α, PKC-β2, p-PKC-α, p-PKC-β2, NF-κB and c-Fos were determined by Western blotting. RESULTS: Neonatal cardiomyocytes cultured in high glucose concentration showed increased cellular diameters, protein level and higher expressions of PKC-α, PKC-β2, p-PKC-α, p-PKC-β2, NF-κB and c-Fos, which was consistent with the increased glucose levels and had statistical significance compared to control group (P<0.01). PKC inhibitor Ro-31-8220 reversed these changes induced by high glucose concentration as showed by decreased cellular diameters, protein level and expression of PKC-α, PKC-β2, p-PKC-α, p-PKC-β2, NF-κB and c-Fos, which had statistical significance compared to high glucose groups (P<0.01). CONCLUSION: High glucose levels induce hypertrophy of cardiomyocytes. PKC inhibitor Ro-31-8220 reverses the effect of high glucose on the cardiac myocytes, which may be via PKC/NF-κB/c-Fos pathway.