The role of mitochondria in progression of high-glucose-inducing injury to human peritoneal mesothelial cells

Objective:To investigate mechanism of high-glucose-inducing injury to human peritoneal mesothelial cells. Methods: (1)The cultured human mesothelial cells were exposed to culture medium containing different concentrations of glucose (1.5%,2.5%,4.25%), with 4.25% mannitol and normal culture medium as control for 48 hours.Then mitochondrial membrane potential(Ψ) and the apoptotic rate were measured by flow cytometry,and caspase-3 activity was measured by ApoAlert(tm) CPP33/Caspase-3Assay kits. (2) The cultured human mesothelial cells were exposed to 4.25% glucose culture medium containing different concentrations of mitochondrial transition pore inhibitor-cyclosporin A (0.01, 0.1μmol/L) for 24 hours, with 4.25% glucose culture medium as control, Then the apoptotic rate was measured by flow cytometry and caspase-3 activity was measured by ApoAlert(tm) CPP33/Caspase-3Assay kits. Results:(1) The percentage of mesothelial cells with loss of mitochondrialΨ was significantly higher in high glucose groups than that in normal culture medium group, which was increasing as glucose concentration increases. The percentage of mesothelial cells with loss of mitochondrialΨ was also significantly higher in 4.25% glucose groups than that in 4.25% mannitol group. (2) Caspase-3 activity and the apoptotic rate of mesothelial cells was significantly higher in 4.25% glucose group and 2.5% glucose group than that in normal culture medium group, but no significant difference in 1.5% glucose group and 4.25% mannitol group compared to in normal culture medium group. Caspase-3 activity and the apoptotic rate of mesothelial cells was also significantly higher in 4.25% glucose group than that in 4.25% mannitol group. Caspase-3 activity and the apoptotic rate of mesothelial cells was increasing as glucose concentration increases. (3) There was significantly positive correlation among the apoptotic rate of mesothelial cells, caspase-3 activity of mesothelial cells and the percentage of mesothelial cells with loss of mitochondrialΨ. (4) Apoptotic rate and caspase-3 activity of mesothelial cells was significantly lower in 0.1μmol/L CsA group than that in control. Conclusion: (1) High-glucose can induce loss of mitochondrial Ψ , apoptosis and caspase-3 activation of human peritoneal mesothelial cells in dose-dependent manner. (2) Caspase-3 activation in progression of high-glucose-inducing apoptosis of human peritoneal mesothelial cells by mitochondria activation.