Ahvaz Hana Hanaee, Mobasheri Hamid, Bakhshandeh Behnaz, Shakhssalim Nasser, Naji Mohammad, Dodel Massumeh, Soleimani Masoud
Laboratory of Membrane Biophysics and Macromolecules, Institute of Biochemistry and Biophysics, University of Tehran, P.O. Box: 13145-1384, Tehran, Iran.
J Nanosci Nanotechnol. 2013 Jul;13(7):4736-43. doi: 10.1166/jnn.2013.7193.
Certain features of electrospun PCL/PLLA nanofibrous scaffolds such as thickness, cross section density, strength, and elastisity can be tailored to mimic the native microenvironment required for bladder tissue engineering. In this study the differentiation of human bladder smooth muscle cells (hBSMCs) cultured on electrospun scaffolds was studied. The scaffolds of aligned PCL/PLLA fibrous with a thickness of about 100 nm, used to implement different mechanical stimulation. Longitudinal (0.7 MPa) and traverse (0.02 MPa) Young's modulus of the constructed hybrid aligned PCL/PLLA scaffolds showed anisotropic orientation of the electrospun fibers. Based on the elastic limit strain, the aligned scaffolds were selected and SEM micrographs used to reveal the outcomes. The application of mechanical forces on seeded scaffolds at physiologic and 0.1 Hz frequencies played crucial role in the differentiation of hBSMCs. Scaffolds were stretched to 2% below the deformation point and the effects of the physiologic and 0.1 Hz stretching frequencies on hBSMCs seeded scaffolds were investigated at gene transcription level. The application of 0.1 Hz stretching forces increased transcriptions of collagen type I/III/IV, elastin, alpha-smooth muscle actin and caldesmon, while at physiologic rate, all of the mentioned genes were down-regulated. On the other hand, exposing human bladder urothelial cells (hBUCs) to 0.1 Hz stretching frequencies promoted transcription of certain functional markers including cytokeratin 8 and 18. We found that mechanical forces with different frequencies exert different regulatory effects on extracellular matrices and contractile genes in hBSMCs and hBUCs that should be considered in tissue engineering strategies.
电纺聚己内酯/聚乳酸纳米纤维支架的某些特性，如厚度、横截面密度、强度和弹性，可以进行调整，以模拟膀胱组织工程所需的天然微环境。在本研究中，对在电纺支架上培养的人膀胱平滑肌细胞（hBSMCs）的分化进行了研究。使用厚度约为100 nm的排列PCL/PLLA纤维支架来施加不同的机械刺激。构建的混合排列PCL/PLLA支架的纵向（0.7 MPa）和横向（0.02 MPa）杨氏模量显示出电纺纤维的各向异性取向。基于弹性极限应变，选择排列的支架，并使用扫描电子显微镜图像来揭示结果。在生理频率和0.1 Hz频率下对接种细胞的支架施加机械力，在hBSMCs的分化中起关键作用。将支架拉伸至低于变形点2%的程度，并在基因转录水平上研究生理频率和0.1 Hz拉伸频率对接种hBSMCs的支架的影响。施加0.1 Hz的拉伸力可增加I/III/IV型胶原蛋白、弹性蛋白、α-平滑肌肌动蛋白和钙调蛋白的转录，而在生理速率下，所有上述基因均下调。另一方面，将人膀胱尿路上皮细胞（hBUCs）暴露于0.1 Hz的拉伸频率下，可促进某些功能标记物（包括细胞角蛋白8和18）的转录。我们发现，不同频率的机械力对hBSMCs和hBUCs中的细胞外基质和收缩基因发挥不同的调节作用，这在组织工程策略中应予以考虑。
