RESUMO
Objective To explore the effect of vascular stress changes on endothelial function recovery and vascular restenosis inhibition in dynamic degradation process of the degradable stent. Methods The material parameters of the hyper-elastic vascular constitutive relationship was fitted, and the stress distribution on the intima of the blood vessel before stent implantation and during dynamic degradation was calculated by numerical simulation. In vitro culture experiments were carried out, and the stretch ratios of the silicon chambers were 0%, 5%, 10% and 15%, respectively, to simulate the mechanical environment at different degradation stages, and to explore the effects of different stretch ratios on growth state of the endothelial cells （ECs）. Results After the stent was completely degraded, the circumferential intimal stress and strain of the vessel were restored to 0.137 MPa and 5.5%, which were close to the physiological parameters (0.122 MPa, 4.8%) before stent implantation. In vitro experiments showed that the survival rate of ECs was the highest under the condition of 0.1 MPa circumferential stress and 5% strain, and adhesion growth could be achieved. Conclusions With the occurrence of stent degradation process, the circumferential stress and strain of the intima were restored to a range close to physiological parameters, which promoted the growth of ECs. The recovery of intimal function could effectively inhibit the process of vascular restenosis. The results can provide the theoretical basis and experimental platform for studying coronary intervention for the treatment of vascular restenosis.
RESUMO
Objective To develop an innovative device for endothelial cell culture in vitro, namely, to develop a vascular endothelial cell culture device based on hemodynamic environment, so as to introduce the development and experimental study of endothelial cell culture device in vitro. Methods A device of dynamic culture system for endothelial cells in vitro on the basis of the existing research was designed with the theory and method of hemodynamics. The shear stress, positive stress and tensile stress existed at the same time in the flow environment. The development and experimental research of the device were described in detail from 5 aspects, such as the development background, structure and composition, design principle, theoretical basis and experimental research. Results The device could accurately simulate the hemodynamic environment of endothelial cells at normal level, with precise control of shear stress in 0-12 Pa range, positive stress in 0-15.96 kPa range, and tensile stress in 0-0.5 MPa range. Conclusions The device can provide a hemodynamic environment which is closer to the physiological conditions of human body, as well as a more ideal experimental environment and means for further exploring the mechanism of vascular intimal injury.