Department of Mechanical Engineering, University of Utah, Salt Lake City, UT, 84112, United States.
Department of Mechanical Engineering, University of Utah, Salt Lake City, UT, 84112, United States; Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, 84112, United States.
J Mech Behav Biomed Mater. 2021 Jun;118:104447. doi: 10.1016/j.jmbbm.2021.104447. Epub 2021 Mar 10.
Arteries play a critical role in carrying essential nutrients and oxygen throughout the brain; however, vessels can become damaged in traumatic brain injury (TBI), putting neural tissue at risk. Even in the absence of hemorrhage, large deformations can disrupt both the physiological and mechanical behavior of the cerebral vessels. Our group recently reported the effect of vessel overstretch on axial mechanics; however, that work did not address possible changes in circumferential mechanics that are critical to the regulation of blood flow. In order to address this in the present work, ovine middle cerebral arteries were isolated and overstretched axially to 10, 20, or 40% beyond the in vivo configuration. Results showed a statistically significant decrease in circumferential stiffness and strain energy, as well as an increase in vessel diameter following 40% overstretch (p < 0.05). These passive changes would lead to a decrease in vascular resistance and likely play a role in previous reports of cellular dysfunction. We anticipate that our findings will both increase understanding of vessel softening phenomena and also promote improved modeling of cerebrovascular mechanics following head trauma.
动脉在向大脑输送必需的营养物质和氧气方面起着至关重要的作用；然而，在创伤性脑损伤 (TBI) 中，血管可能会受损，使神经组织面临风险。即使没有出血，大的变形也会破坏大脑血管的生理和机械性能。我们小组最近报告了血管过度拉伸对轴向力学的影响；然而，该研究并未涉及对血流调节至关重要的周向力学的可能变化。为了解决这个问题，我们在本研究中分离了绵羊大脑中动脉，并将其轴向拉伸至超过体内形态 10%、20%或 40%。结果显示，在 40%的过度拉伸后，周向刚度和应变能显著降低，血管直径增加（p<0.05）。这些被动变化会导致血管阻力降低，可能在前述细胞功能障碍的报告中发挥作用。我们预计，我们的发现将不仅增加对血管软化现象的理解，还将促进头部创伤后脑血管力学的改进建模。
