Corr David T, Gallant-Behm Corrie L, Shrive Nigel G, Hart David A
Biomedical Engineering Department, Rensselaer Polytechnic Institute, Troy, New York, USA.
Wound Repair Regen. 2009 Mar-Apr;17(2):250-9. doi: 10.1111/j.1524-475X.2009.00463.x.
A new method to test axial and transverse tensile properties of skin was developed to improve our understanding of skin mechanical behavior, and how it changes following injury and formation of a scar. Skin tissue was evaluated at 70 days following full-thickness wounding in juvenile female pigs (N=14). Samples were taken in the axial (cranial-caudal) and transverse (dorsal-ventral) directions, for both scar tissue and uninjured skin, and were evaluated mechanically in vitro using a protocol of stress relaxation followed by tensile failure. Uninjured skin was more compliant, with a larger toe-in region, and faster load relaxation, in the axial direction than the transverse. Such directional differences were not present in high-load responses, such as linear stiffness or failure properties. When compared with uninjured skin, scars displayed a similar linear stiffness, with considerably reduced failure properties, and reduced low-load compliance. Scars showed no directional differences in low-load behavior, viscous response, or failure properties. These findings suggest morphological changes that may occur with injury that are consistent with the viscoelastic and directional changes observed experimentally. This improved understanding of how injury affects skin biomechanical function provides valuable information necessary for the design of successful grafting procedures and tissue-engineered skin replacements.
为了增进我们对皮肤力学行为及其在受伤和形成瘢痕后如何变化的理解，开发了一种测试皮肤轴向和横向拉伸特性的新方法。在幼年雌性猪（N = 14）全层伤口愈合70天后对皮肤组织进行评估。从瘢痕组织和未受伤皮肤中，在轴向（头-尾）和横向（背-腹）方向采集样本，并在体外使用应力松弛协议继以拉伸破坏的方案进行力学评估。未受伤皮肤在轴向比横向更具顺应性，具有更大的初始弯曲区域和更快的负荷松弛。在诸如线性刚度或破坏特性等高负荷响应中不存在这种方向差异。与未受伤皮肤相比，瘢痕显示出相似的线性刚度，但破坏特性显著降低，低负荷顺应性也降低。瘢痕在低负荷行为、粘性响应或破坏特性方面没有方向差异。这些发现表明损伤可能导致的形态学变化与实验观察到的粘弹性和方向变化一致。对损伤如何影响皮肤生物力学功能的这种更好理解为成功的移植手术和组织工程皮肤替代物的设计提供了必要的有价值信息。
