Activation of calcium-sensing receptors is associated with apoptosis in cardiomyocytes under simulated ischemia/reperfusion / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To examine the association of activation of calcium-sensing receptors (CaSR) with apoptosis in cardiomyocytes under simulated ischemia/reperfusion.</p><p><b>METHODS</b>Ventricular cardiomyocytes of neonatal rats were incubated in ischemia-mimetic solution for 2 h, then re-incubated in normal culture medium for 24 h to establish a model of simulated ischemia/reperfusion (I/R). Cell apoptosis was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL assay). The expression of CaSR mRNA was detected by reverse transcriptase polymerase chain reaction (RT-PCR). The expression of Caspase -3 and Bcl-2 was detected by Western blotting.</p><p><b>RESULT</b>The simulated I/R enhanced the expression of CaSR and cardiomyocyte apoptosis. GdCl(3), a specific activator of CaSR, further increased the expression of CaSR and cardiomyocyte apoptosis, along with upregulation of Caspase-3 and downregulation of Bcl-2.</p><p><b>CONCLUSION</b>CaSR is associated with I/R injury and apoptosis in neonatal rat ventricular cardiomyocytes via suppressing Bcl-2 and promoting Caspase -3 expression.</p>

Hepatocyte growth factor attenuates ischemia/reperfusion induced cardiomyocyte apoptosis via downregulating calcium sensing receptor expression / 中华心血管病杂志

<p><b>OBJECTIVE</b>To examine whether the anti-apoptotic effect of hepatocyte growth factor (HGF) in cardiomyocytes underwent ischemia/reperfusion (I/R) is associated with downregulation of calcium sensing receptor (CaSR) mRNA expression.</p><p><b>METHODS</b>Neonatal rat cardiomyocytes were isolated and randomly divided into 7 groups: control, I/R, GdCl(3), GdCl(3) + NiCl(2) + CdCl(2), GdCl(3) + LY294002, GdCl(3) + HGF, GdCl(3) + HGF + LY294002.I/R was established by incubating primary neonatal rat ventricular cardiomyocytes in ischemia-mimetic solution for 2 h, then reincubated in normal culture medium for 24 h. Cardiomyocyte apoptosis was detected by TUNEL. The expression of CaSR mRNA was detected by reverse transcriptase polymerase chain reaction (RT-PCR). The expression of Caspase-3, Bcl-2 and Phosphoinositide-3 Kinase (PI3K) was analyzed by Western blot.</p><p><b>RESULTS</b>I/R enhanced the expression of CaSR mRNA (I/R: 2.62 ± 0.41, control: 1.00 ± 0.31, P < 0.01) and cardiomyocyte apoptosis [I/R: (15.32 ± 2.54)%, control: (2.90 ± 1.45)%, P < 0.01]. GdCl(3) further increased the expression of CaSR mRNA (GdCl(3): 4.46 ± 0.62, I/R: 2.62 ± 0.41, P < 0.01) and cardiomyocyte apoptosis [GdCl(3): (25.36 ± 2.60)%, I/R: (15.32 ± 2.54)%, P < 0.01], along with upregulation of Caspase-3 (GdCl(3): 1.93 ± 0.28, I/R: 1.50 ± 0.21, P < 0.01), downregulation of Bcl-2 (GdCl(3): 0.82 ± 0.18, I/R: 1.71 ± 0.30, P < 0.01) and PI3K phosphorylation inhibition (I/R: 0.87 ± 0.08, GdCl(3): 0.61 ± 0.07, P < 0.01). Combination of GdCl(3) with LY294002 further enhanced cardiomyocytes apoptosis [GdCl(3) + LY294002: (32.6 ± 3.42)%, GdCl(3): (25.36 ± 2.60)%, P < 0.01] but did not affect CaSR mRNA expression (GdCl(3) + LY294002: 4.27 ± 0.56, GdCl(3): 4.46 ± 0.62, P > 0.05). HGF decreased I/R- and GdCl(3)-induced apoptosis [GdCl(3) + HGF: (11.8 ± 1.89)%, GdCl(3): (25.36 ± 2.60)%, P < 0.05] by suppressing Caspase-3 (GdCl(3) + HGF: 1.12 ± 0.23, (GdCl(3): 1.93 ± 0.28, P < 0.05; GdCl(3) + HGF + LY294002: 1.87 ± 0.31, GdCl(3) + LY294002: 3.86 ± 0.47, P < 0.05) and promoting Bcl-2 (GdCl(3) + HGF: 2.56 ± 0.54, GdCl(3): 0.82 ± 0.18, P < 0.05; GdCl(3) + HGF + LY294002: 1.68 ± 0.28, GdCl(3) + LY294002: 0.68 ± 0.13, P < 0.05) and PI3K phosphorylation expression (GdCl(3) + HGF: 2.87 ± 0.21, GdCl(3): 0.61 ± 0.07, P < 0.05; GdCl(3) + HGF + LY294002: 2.01 ± 0.14, GdCl(3) + LY294002: 0.44 ± 0.10, P < 0.05) in accordance with downregulation of CaSR mRNA expression (GdCl(3) + HGF: 1.46 ± 0.37, GdCl(3): 4.46 ± 0.62, P < 0.01).</p><p><b>CONCLUSION</b>HGF exerts protective role in I/R-induced apoptosis at least in part by inhibiting CaSR mRNA expression along with promoting Bcl-2, suppressing Caspase-3 expression and stimulating PI3K phosphorylation signaling pathway.</p>