不锈钢支架的塑性变形量对血管壁细胞行为的影响

The Effect of Plastic Deformation of Stainless Steel Stent on the Behavior of Vascular Wall Cells

摘要: 心血管疾病介入治疗中大量使用金属支架。支架撑开后，各位置塑性变形量不同，与血管壁/细胞直接接触并发生相互作用时，金属塑性变形量将对表面血管壁细胞行为产生影响。基于此，本文以生物医用不锈钢为对象，针对血管支架扩张后的塑性变形，设定不同变形量ε (20%、60%、100%)，并借助万能试验机制备相应样品；通过光学显微镜(OM)、扫描电子显微镜(SEM)、台阶仪等对样品表面进行材料形貌表征；通过水接触角测试、表面能分量计算等对样品表面进行理化性质测定；通过荧光染色法和CCK-8 (Cell Counting Kit-8)细胞活性检测对血管壁细胞的生长行为进行评价。结果显示，因塑性变形量的差异，内皮细胞在ε = 60%时细胞活性最好，平滑肌细胞的细胞活性没有明显差异；当ε > 60%时，内皮细胞与平滑肌细胞的生长方向均趋向于与拉伸方向平行。本文研究结果提示，对血管支架进行恰当构型设计，调整服役过程中支架不同位置的塑性变形量，改善血管壁细胞行为，具有重要意义。

Abstract: Metal stents are widely used in interventional therapy of cardiovascular diseases. The amount of plastic deformation is different in each position when the stent is expanded in the vessel. When the stent is in direct contact with the cells of the vessel wall and interacts with them, the amount of plas-tic deformation of the metal will affect the behavior of the cells of the vessel wall. Based on this, this paper takes biomedical stainless steel as the object, and sets different amounts of deformation (20%, 60%, 100%) for the plastic deformation of stent after expansion. The universal testing machine was used to stretch the biomedical stainless steel. The surface morphology of the samples was characterized by optical microscope (OM), scanning electron microscope (SEM) and step measuring instrument. The physical and chemical properties of the surface of the sample were measured by water contact angle (WCA) the calculation of surface energy component. The growth behavior of the cells of the vessel wall was evaluated by fluorescence staining and cell counting kit-8 (CCK-8). The results show that the endothelial cells have the best activity when the deformation is 60%, but the smooth muscle cells have no significant difference. When the deformation is more than 60%, the growth direction of endothelial cells and smooth muscle cells tend to be parallel to the stretching direction. The results of this study suggest that it is of great significance to design the appropriate configuration of the stent, as it can adjust the plastic deformation of different positions of the stent during the service process, and improve the cell behavior on the vascular wall.