Biomechanical characterization of the urethral musculature
Biomechanical characterization of the urethral musculature
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DOI：
10.1152/ajprenal.00330.2005
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发表时间：
2006-05-01
影响因子：
4.2
通讯作者：
Vorp, DA
中科院分区：
文献类型：
--
作者：
Jankowski, RJ;Prantil, RL;Vorp, DA
严格的研究尿道结构解剖和生物力学功能之间的关联是必要的，以促进对尿道病变的发展，进展和治疗的理解。一个离体模型被用来定义女性尿道的主动（肌肉）元素相对于其被动（noncontractile）元素的相对生物力学贡献。在一系列施加的管腔内压力（0至20 mmHg）下测试来自雌性成年大鼠的整个尿道，同时用激光测微计测量尿道中段外径。在单独的平滑肌（N-ω-硝基-L-精氨酸、苯丙氨酸）、单独的横纹肌（硝普钠、阿托品、六甲铵、乙酰胆碱）诱导收缩期间或在两种肌肉的集体激活期间（N-ω-硝基-L-精氨酸、苯丙氨酸、乙酰胆碱）进行活性组织表征。随后收集成对的被动生物力学响应允许确定与内在肌肉收缩功能相关的参数。每个肌肉层的激活显著影响组织的生物力学响应。肌肉反应性的措施，在广泛的范围内的持续对立的压力表明，激活横纹肌成分是约三分之一的有效激活平滑肌在抵抗组织变形。在这些条件下，横纹肌成分产生的最大周向应力也被确定为平滑肌产生的最大周向应力的约三分之一（748 +/- 379 vs. 2，229 +/- 409 N/m（2））。实验定量地揭示了内在尿道平滑肌和横纹肌层的相对影响，它们对尿道的机械性能和最大功能反应的影响，在完全没有外部影响的情况下施加腔内应力。
Rigorous study of the associations between urethral structural anatomy and biomechanical function is necessary to advance the understanding of the development, progression, and treatment of urethral pathologies. An ex vivo model was utilized to define the relative biomechanical contributions of the active ( muscle) elements of the female urethra relative to its passive ( noncontractile) elements. Whole urethras from female, adult rats were tested under a range of applied intraluminal pressures ( 0 to 20 mmHg) as a laser micrometer simultaneously measured midurethral outer diameter. Active tissue characterization was performed during induced contraction of either smooth muscle alone (N-omega-nitro-L-arginine, phenylephrine), striated muscle alone ( sodium nitroprusside, atropine, hexamethonium, acetylcholine), or during collective activation of both muscles (N-omega-nitro-L-arginine, phenylephrine, acetylcholine). The subsequent collection of paired passive biomechanical responses permitted the determination of parameters related to intrinsic muscle contractile function. Activation of each muscle layer significantly influenced the biomechanical responses of the tissue. Measures of muscle responsiveness over a wide range of sustained opposing pressures indicated that an activated striated muscle component was approximately one-third as effective as activated smooth muscle in resisting tissue deformation. The maximum circumferential stress generated by the striated muscle component under these conditions was also determined to be approximately one-third of that generated by the smooth muscle (748 +/- 379 vs. 2,229 +/- 409 N/m(2)). The experiments quantitatively reveal the relative influence of the intrinsic urethral smooth and striated muscle layers with regard to their effect on the mechanical properties and maximum functional responses of the urethra to applied intralumenal stresses in the complete absence of extrinsic influences.