α-硫辛酸对高糖诱导下乳鼠心肌细胞作用

Protective effects of α-lipoic acid on high glucose induced cardiac myocytes hypertrophy in neonatal rats

目的探讨α-硫辛酸对高糖诱导的乳鼠心肌细胞肥大保护作用及其机制。方法取出生1～3 d乳鼠心尖部心肌细胞原代培养,用低糖培养基培养48 h后分为对照组、高糖组(25.5 mmol/L)、α-硫辛酸组(高糖+50、100、200、300 mg/L)、蛋白激酶C(PKC)抑制剂组(高糖+PKC抑制剂50 nmol/L)、核转录因子-κB(NF-κB)抑制剂组(高糖+NF-κB抑制剂5 mmol/L);细胞培养48 h,检测细胞表面积以及蛋白含量,Wesrtern blot法检测PKC-α、NF-κB、肿瘤坏死因子-α(TNF-α)、立早基因c-fos蛋白表达。结果与对照组比较,高糖组乳鼠心肌细胞肥大、细胞表面积增大、蛋白含量增多,心肌细胞内PKC-α(0.89±0.03)、NF-κB(0.88±0.14)、c-fos(0.62±0.14)、TNF-α(0.85±0.05)蛋白表达均升高(P<0.05);α-硫辛酸能够减轻乳鼠心肌细胞肥大,使心肌细胞表面积减小、蛋白含量减少(P<0.05),与高糖组比较,α-硫辛酸300 mg/L组细胞内PKC-α(0.44±0.07)、NF-κB(0.24±0.03)、TNF-α(0.39±0.05)、c-fos(0.15±0.06)蛋白表达均下降(P<0.05)。结论α-硫辛酸可抑制高糖诱导的乳鼠心肌细胞肥大,其机制可能与抑制PKC/NF-κB/TNF-α/c-fos的信号转导通路有关。

Objective To explore the protective effect and its mechanism of α-lipoic acid on high glucose-induced neonatal rat cardiac myocyte hypertrophy.Methods Apical myocardial cells of neonatal rats（1-3 days after the birth） were cultured for 48 hours with low glucose medium and then divided into a control group,a high glucose group（25.5 mmol/L）,four α-lipoic acid groups（high sugar ＋50,100,200,300 mg/L alpha-lipoic acid）,a protein kinase C（PKC） inhibitor group（high sugar＋PKC inhibitor 50 nmol/L）,and a nuclear transcription factor-κB（NF-κB） inhibitor group（high sugar＋NF-κB inhibitor 5 mmol/L）.The cells were cultured for 48 hours to detect cell surface area and protein content.PKC-α,NF-κB,tumor necrosis factor-α（TNF-α）,and c-fos protein expression were detected with western blot.Results Compared with the control group,cardiac myocyte hypertrophy,increased cell surface area,increased protein content,increased PKC-α（0.89±0.03）,NF-κB（0.88±0.14）,c-fos（0.62±0.14）,and TNF-α（0.85±0.05） in myocardial cells wee observed（P0.01 for all）.The treatment of α-lipoic acid resulted in cardiac myocyte hypertrophy,decrease of myocardial cell surface area and protein content（P0.05 for all）.Compared with those of high sugar group,intracellular PKC-α（0.50±0.07）,NF-κB（0.24±0.03）,TNF-α（0.39±0.05）,and c-fos（0.15±0.06） protein expression were significantly decreased in the rats of 300 mg/L α-lipoic acid group（P0.01 for all）.Conclusion α-lipoic acid can inhibit cardiac myocyte hypertrophy induced by high glucose in neonatal rats and its mechanism may be related to the inhibition of the signal transduction pathway of PKC/NF-κB/TNF-α/c-fos.