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Protein kinase C#delta# is possibly involved in the transition from hypertrophy to apoptosis of myocardiocytes

Guo Wangang, Yu Zhibin, Xie Manjiang

Department of Aerospace Physiology, the Fourth Military Medical University.Xi'an 710032,Shaanxi

Abstract

Cardiac hypertrophy is an adaptive process to an increased hemodynamic overload. However, the adaption may lead to the fragility of myocardium facing pathological stimuli. In the present study, experiments were designed to explore the susceptibility of hypertrophic myocardiocytes to apoptotic stimuli and the role of protein kinase C#delta# (PKC#delta#) during the transition from hypertrophy to apoptosis. Endothelin-1 (ET-1)-treated cardiomyocytes were used as model of cardiac hypertrophy. Angiotensin II (Ang II) was used as an apoptotic stimulus. Cell surface area was measured to determine the extent of hypertrophy. The apoptotic rate in cardiomyocytes was detected by hoechst33258. (1) Cell surface area was increased by 42.5% and 67.3% following 1 nmol/L and 10 nmol/L ET-1, respectively, as compared with serum-free cultured myocytes. So the mildly and moderately hypertrophic myocyte models were set up. (2) Apoptotic rates in serum-free cultured, mildly and moderately hypertrophic myocytes after Ang II treatment were (15.54±1.32)%, (20.65±1.40)% and (29.33±3.52)%, respectively. It suggests that hypertrophic myocytes are more susceptible to apoptotic stimulus. (3) Rottlerin, a specific inhibitor of PKC#delta#, depressed apoptotic rates induced by Ang II to (15.88±2.25)% in mildly hypertrophic cells and (15.01±1.37)% in moderately hypertrophic myocytes; but rottlerin did not affect apoptotic rate induced by Ang II in serum-free cultured myocytes. These results suggest that inhibition of PKC#delta# can reduce Ang II-induced apoptosis of hypertrophic cardiomyocytes and that PKC#delta# is possibly involved in the apoptotic process of hypertrophied cardiomyocytes.

Key words: myocytes,cardiac;Hypertrophy;Apoptosis;protein kinase C#delta#;rottlerin

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Citing This Article：

Guo Wangang, Yu Zhibin, Xie Manjiang. Protein kinase C#delta# is possibly involved in the transition from hypertrophy to apoptosis of myocardiocytes. Acta Physiol Sin 2006; 58 (3): (in Chinese with English abstract).