Department of Biomedical Engineering, University of California Irvine, Irvine, CA, USA.
Department of Urology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA.
Acta Biomater. 2023 Oct 1;169:130-137. doi: 10.1016/j.actbio.2023.08.017. Epub 2023 Aug 13.
The tunica albuginea (TA) of the penis is an elastic layer that serves a structural role in penile erection. Disorders affecting the TA cause pain, deformity, and erectile dysfunction. There is a substantial clinical need for engineered replacements of TA, but data are scarce on the material properties and biochemical composition of healthy TA. The objective of this study was to assess tissue organization, protein content, and mechanical properties of porcine TA to establish structure-function relationships and design criteria for tissue engineering efforts. TA was isolated from six pigs and subjected to histomorphometry, quantification of collagen content and pyridinoline crosslinks, bottom-up proteomics, and tensile mechanical testing. Collagen was 20 ± 2%/wet weight (WW) and 53 ± 4%/dry weight (DW). Pyridinoline content was 426 ±131 ng/mg WW, 1011 ± 190 ng/mg DW, and 45 ± 8 mmol/mol hydroxyproline. Bottom-up proteomics identified 14 proteins with an abundance of >0.1% of total protein. The most abundant collagen subtype was type I, representing 95.5 ± 1.5% of the total protein in the samples. Collagen types III, XII, and VI were quantified at 1.7 ± 1.0%, 0.8 ± 0.2%, and 0.4 ± 0.2%, respectively. Tensile testing revealed anisotropy: Young's modulus was significantly higher longitudinally than circumferentially (60 ± 18 MPa vs. 8 ± 5 MPa, p < 0.01), as was ultimate tensile strength (16 ± 4 MPa vs. 3 ± 3 MPa, p < 0.01). Taken together, the tissue mechanical and compositional data obtained in this study provide important benchmarks for the development of TA biomaterials. STATEMENT OF SIGNIFICANCE: The tunica albuginea of the penis serves an important structural role in physiologic penile erection. This tissue can become damaged by disease or trauma, leading to pain and deformity. Treatment options are limited. Little is known about the precise biochemical composition and biomechanical properties of healthy tunica albuginea. In this study, we characterize the tissue using proteomic analysis and tensile testing to establish design parameters for future tissue engineering efforts. To our knowledge, this is the first study to quantify tissue anisotropy and to use bottom-up proteomics to characterize the composition of penile tunica albuginea.
阴茎的白膜是一种弹性层，在阴茎勃起中起着结构作用。影响白膜的疾病会导致疼痛、畸形和勃起功能障碍。临床上迫切需要工程替代白膜，但关于健康白膜的材料特性和生化组成的数据却很少。本研究的目的是评估猪白膜的组织学结构、蛋白质含量和力学性能，以建立结构-功能关系和设计组织工程的标准。从六头猪中分离白膜并进行组织形态计量学、胶原含量和吡啶交联定量、自上而下的蛋白质组学和拉伸力学测试。胶原占湿重的 20±2%/湿重（WW）和干重的 53±4%/干重（DW）。吡啶啉含量为 426±131ng/mgWW，1011±190ng/mgDW，45±8mmol/mol羟脯氨酸。自上而下的蛋白质组学鉴定出 14 种丰度大于总蛋白 0.1%的蛋白质。最丰富的胶原亚型是 I 型，占样品中总蛋白的 95.5±1.5%。胶原类型 III、XII 和 VI 的定量分别为 1.7±1.0%、0.8±0.2%和 0.4±0.2%。拉伸试验显示各向异性：纵向杨氏模量明显高于横向（60±18MPa 比 8±5MPa，p<0.01），极限拉伸强度也是如此（16±4MPa 比 3±3MPa，p<0.01）。总之，本研究获得的组织力学和组成数据为白膜生物材料的开发提供了重要的基准。研究意义：阴茎的白膜在生理勃起中起着重要的结构作用。这种组织可能因疾病或创伤而受损，导致疼痛和畸形。治疗选择有限。关于健康白膜的确切生化组成和生物力学特性知之甚少。在这项研究中，我们使用蛋白质组分析和拉伸测试来描述组织，以建立未来组织工程的设计参数。据我们所知，这是首次定量研究白膜的各向异性并使用自上而下的蛋白质组学来描述阴茎白膜的组成。
