ABSTRACT
The influence of an external electric field (EEF) on the deprotonation reaction of Fe3+-solvated molecules was studied using reactive molecular dynamics (ReaxFF MD) simulations. It was examined in terms of changes in structural properties, kinetics, system energy, and reaction products under an EEF, and the results were further verified experimentally. The research results show that the presence of an EEF will affect the distribution of water molecules around Fe3+ and provide energy for the fracturing of O-H bonds. The increase in the state of reaction products represented by H+ also suggests that the EEF can promote the deprotonation reaction of Fe3+-solvated molecules. The viscosity of the system is significantly increased under an EEF. The experimental results for verification show that the pH of the FeCl3 solution is reduced under the action of an EEF, which means that the hydrolysis of Fe3+ has been promoted. The experimental results are consistent with the results of the MD simulations.
ABSTRACT
BACKGROUND: Long-term peritoneal dialysis (PD) results in functional and structural alterations of the peritoneal membrane. Previous studies have suggested that high glucose (HG) could induce transdifferentiation of peritoneal mesothelial cells into myofibroblasts, but the molecular mechanisms of HG-induced epithelial-to-mesenchymal transition (EMT) of human peritoneal mesothelial cells (HPMCs) are unclear. This study was undertaken to elucidate the effects and mechanisms of Twist on HG-induced EMT of HPMCs. METHODS: HPMCs were exposed to 5.6 mM glucose [normal glucose (NG)], 50 mM glucose (HG) or 50 mM glucose with Si-Twist or pcDNA3.1-Twist. Western blot and immuocytochemistry were performed to determine Twist, E-cadherin and α-smooth muscle actin (α-SMA) protein expression. MMP2 and MMP9 were detected by zymography. Rats were daily instilled with PD fluid and lipopolysaccharide (LPS) or sodium chloride during 6 weeks. Histological analyses were carried out in parietal peritoneum. Twist was detected by western blotting. RESULTS: Twist and α-SMA protein and immuocytochemistry were significantly increased in HG-conditioned media compared to NG media. E-cadherin protein was lower in pcDNA3.1-Twist-transfected HPMCs compared to pcDNA3.1 cells. Twist protein was upregulated 12 h after HG stimulation. MMP9 was increased in pcDNA3.1-Twist-transfected HPMCs compared to pcDNA3.1 cells. Exposure of rat peritoneum to PD fluid and LPS resulted in an increase of extracellular matrix deposition. Twist and α-SMA were stained in the PD fluid group and compared to the control group. Twist protein was significantly increased in the PD group. CONCLUSIONS: In conclusion, HG-induced Twist expression might contribute to EMT of HPMCs. Twist may control EMT of HPMCs by regulating MMP9.
