内皮素-1与PGF_(2α)单独或联合作用对心肌细胞的影响

INDEPENDENT OR COMBINED EFFECTS OF ENDOTHELIN-1 AND PROSTAGLANDIN F_(2α) ON CARDIOMYOCYTES

目的:观测ET1与PGF2α单独或联合作用对新生大鼠心肌细胞面积与凋亡率的影响,以探讨心肌细胞肥大与凋亡的关系。方法:分离培养新生大鼠心肌细胞,采用鬼笔环肽(phalloidin)荧光染色(定性)与细胞面积测量(定量)两种方法检测心肌细胞肥大;以Hoechst33258荧光染色检测心肌细胞凋亡。结果:Phalloidin荧光染色显示ET1或PGF2α单独处理组,心肌细胞肌原纤维纹理清晰,纤维增多且沿细胞长轴方向排列。而ET1与PGF2α联合处理48h组的肌原纤维出现纹理模糊与断裂现象。ET1与PGF2α诱导心肌细胞肥大呈现一定的量效关系:10nmol/LET1处理24h组心肌细胞面积较对照组增加68%,100nmol/LET1组增加84%。10nmol/LPGF2α组增加28%,100nmol/LPGF2α组增加106%。ET1与PGF2α可协同引起心肌细胞肥大,但缺乏叠加效应:10nmol/L ET1与10nmol/LPGF2α联合作用组增加80%;10nmol/LET1与100nmol/LPGF2α组增加122%;而100nmol/L ET1与10nmol/LPGF2α组增加96%;100nmol/LET1与100nmol/LPGF2α组增加199%。ET1与PGF2α单独作用缺乏明显的促心肌细胞凋亡作用。ET1与PGF2α联合作用24h对心肌细胞凋亡率亦无明显影响,作用48h则使心肌细胞凋亡率呈显著性增加。ET1或PGF2α先引起心肌细胞肥大后,促肥大因子亦可诱导心肌细胞凋亡,且心肌细胞凋亡率?

Aim: To elucidate the independent or combined effects of endothelin-1(ET-1) and prostaglandin F_(2α)(PGF_(2α)) on cardiomyocytes and investigate the relationship between hypertrophy and apoptosis of cardiomyocytes. Methods: Cultured neonatal rat cardiomyocytes were stained with FITC-conjugated phalloidin and eosin to detect the cardiomyocyte hypertrophy evidenced by increased sarcomeric structure and cell size. Cardiomyocytes were stained with Hoechst 33258 to detect apoptotic nuclei showing features of condensation and fragmentation. Results: Cardiomyocyte hypertrophy induced by ET-1 or PGF_(2α) shown a dose dependent effect. The area of cardiomyocytes treated by 10 nmol/L or 100 nmol/L of ET-1 for 24 h increased 68% or 84% as compared with control, respectively. The area of cardiomyocytes exposed to 10 nmol/L or 100 nmol/L of PGF_(2α) for 24 h increased 28% or 106% as compared with control, respectively. The ET-1 and PGF_(2α) had a synergic effect on cardiomyocyte hypertrophy, but not superimposed effect. The area of cardiomyocytes increased 80%, 122%, 96%, and 199% in 10 nmol/L ET-1 plus 10 nmol/L PGF_(2α), 10 nmol/L ET-1 plus 100 nmol/L PGF_(2α), 100 nmol/L ET-1 plus 10 nmol/L PGF_(2α), and 100 nmol/L ET-1 plus 100 nmol/L PGF_(2α) group, respectively. There were no changes in apoptotic rate of cardiomyocytes treated by ET-1 or PGF_(2α) alone for 48 h. The apoptotic rate of cardiomyocytes also didn't increase in ET-1 plus PGF_(2α) treatment for 24 h groups, but significantly increased in ET-1 plus PGF_(2α) treatment for 48 h groups. ET-1 or PGF_(2α) could induce an increase in apoptotic rate of hypertrophic cardiomyocytes. There was a positive relationship between hypertrophic extent and apoptotic rate in cardiomyocytes. Conclusion: The cardiomyocytes treated by ET-1 or PGF_(2α) alone only show hypertrophy, but treatment of ET-1 plus PGF_(2α) for 48 h induces apoptosis of cardiomyocytes.