三氧化二砷诱导心肌细胞凋亡对PKC-ε的影响

Alteration of protein kinase C-ε in arsenic trioxide-induced cardiomyocyte apoptosis

目的探讨三氧化二砷诱导新生乳鼠心室肌细胞(NRVCs)凋亡过程中对PKC-ε的影响。方法 NRVCs随机分为6组:正常组(Ctrl)、三氧化二砷高、中、低剂量组(10、5、2μmol.L-1)、PKC-ε抑制剂(100 nmol.L-1)+三氧化二砷(5μmol.L-1)组、PKC-ε抑制剂(100 nmol.L-1)组。采用MTT法检测细胞活力,Hoechst 33342染色和TUNEL法检测细胞凋亡。应用Western blot技术检测PKC-ε蛋白表达水平。结果三氧化二砷(5、10μmol.L-1)孵育24 h剂量依赖性地降低NRVCs活力,诱导NRVCs凋亡。此外,三氧化二砷(5μmol.L-1)增加PKC-ε蛋白的表达。而抑制PKC-ε能够进一步促进三氧化二砷降低NRVCs活力,并加重NRVCs凋亡。结论三氧化二砷上调PKC-ε蛋白水平,而抑制PKC-ε促进三氧化二砷加重心肌细胞凋亡。本研究表明三氧化二砷能够引起PKC-ε表达异常改变,提示PKC-ε可能参与三氧化二砷诱导心肌细胞凋亡的病理过程。

Aim To explore the effect of arsenic triox- ide-induced neonatal rat ventricular cell （NRVCs） ap- optosis on PKC-ε. Methods NRVCs were randomly divided into six groups ： control （ctrl） group, high, me- dium, low dosage of arsenic trioxide （10, 5, 2 μmol . L-1 ） groups, PKC-ε inhibitor （PKC-ε-TIP） group, PKC-ε-TIP ＋ arsenic trioxide （5pμmol . L-1 ） group. MTT was used to detect NRVCs viability. Ho- echst33342 stainning and Tunel assay were carried out to detect NRVCs apoptosis. Western blot technology was applied to assess the protein expression of PKC-e in NRVCs. Results Incubation with arsenic trioxide （5,10 μmol . L-1） for 24 h dose-dependently de- creased NRVCs viability, and induced NRVCs apopto-sis. In addition, arsenic trioxide （5 μmol . L-1 ） sig- nificantly increased the protein expression of PKC-ε. However, inhibition the expression of PKC-ε could promote arsenic trioxide to further decrease NRVCs vi- ability, and aggravate apoptosis. Conclusions Arse- nic trioxide upregulates the level of PKC-a protein, in- hibition of the expression of PKC-ε promoted arsenic trioxide to aggravate cardiomyocyte apoptosis. It sug- gests that arsenic trioxide could cause the abnormal al- teration of PKC-ε. It reveals that PKC-ε might be involved in the pathology of arsenic trioxide-induced cardiomyocyte apoptosis.