多模化仿生应力调控组织工程膀胱细胞生物学功能及其相关力学响应机制的研究

Researches in recent years have been focusing on inventing material for replacing or substituting the bladder by tissue engineering approaches. From the previous researches, several generations of bladder cells cultivated, the following cell conditions were observed: failure to thrive, cells , cells cast-off from the stents, loss of the original cells function, all of which resulted from the absence of stress stimulation. As is shown in the result of urinary diversion in fetal bladder, stress is key to bladder development. From our preliminary researches, it can be concluded that Stress of different kinds boasts different biological functions and the purposes of promoting or maintaining cells growth, differentiation and function maturity cannot be met by solely applying stretch or static pressure stimulated bladder cells in vitro the cultivation systems. To serve the purpose, muti-mode biomimetic stresses, a cultivation system capable of generating stretch stress and static pressure simultaneously or consecutively is to be created, can be used to both regulate cells growth and promote cells differentiation and function maturity, which is conductive to the creation of an active functional tissue engineering bladder. In addition, the mechanical responding mechanism of cells will be examined, which is good for precise regulation and control on the biological behavior of bladder cells.

近些年来，以组织工程学的方法来构建膀胱修补或替代材料成为研究焦点。在以往研究中发现膀胱细胞培养多代后出现生长停滞、去细胞分化、细胞从支架材料脱落及细胞丧失原有功能，究其原因在于缺少应力的刺激，源于一胚胎尿液转流模型的研究发现：应力是膀胱发育的重要条件。我们前期研究结果示：不同种类应力产生物效应具有差异，单独地运用牵张应力或静水压施加培养系统将无法达到既能促进膀胱细胞生长又能促进或维持膀胱细胞分化及功能成熟的目的，需要构建一套多模化应力施加培养系统，能同时或交替施加牵张应力和静水压，既能调控膀胱细胞生长又能促进膀胱细胞功能分化成熟，最终将有助于构建有功能活性的组织工程膀胱。进一步探讨细胞对力学的响应机制，有利精确调控膀胱细胞的生物学行为。

基于我们以往的应力施加培养系统的研究基础上构建一套多模化仿生应力施加培养系统，膀胱细胞与硅胶膜复合培养，并运用多模化仿生应力培养系统对其施加不同强度的应力，结果发现仿生应力能促进膀胱细胞增殖，尿路上皮细胞分化功能成熟标志物尿溶蛋白II的表达，膀胱平滑肌细胞收缩及分化相关的α-平滑肌肌动蛋白和平滑肌蛋白22-α的表达，80cmH2O+4%的仿生应力促进膀胱细胞增殖及分化成熟的功能蛋白的表达效果最佳；尿路上皮细胞及膀胱平滑肌细胞有类似的力学响应机制，整合素、局部粘着斑激酶在力学信号转导中起到关键作用，这些研究将有益于掌握并精确调控组织工程膀胱细胞生长、分化功能成熟和组织结构合理化的培养微环境。此外，不适的应力可造成膀胱细胞损害，发生功能障碍，模拟体内膀胱病理状态下所受到的应力，对尿路上皮细胞施加持续性高强度复合应力，检测到炎症指标上升，并发现β3肾上腺素能受体参与炎症指标的调节，这也将有助于我们了解应力在组织重构过程中的作用和诸如在膀胱出口梗阻等疾病中的机理，并有助于针对这些机理采取新的更为有效的应对策略，在泌尿外科疾病基础探索领域也具有重要意义。