Passive biaxial mechanical properties of the rat bladder wall after spinal cord injury
Passive biaxial mechanical properties of the rat bladder wall after spinal cord injury
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DOI：
10.1016/s0022-5347(05)65137-3
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发表时间：
2002-05-01
影响因子：
6.6
通讯作者：
Chancellor, MB
中科院分区：
文献类型：
--
作者：
Gloeckner, DC;Sacks, MS;Chancellor, MB
目的：脊髓损伤后膀胱壁力学性质的改变可改变膀胱顺应性和膀胱壁张力，导致传入神经活动的改变和反射机制的异常。据我们所知，我们报告了第一次将双轴力学测试应用于正常膀胱壁，并展示了脊髓损伤后这些特性是如何变化的。材料与方法：取250 ~ 300 gm的成年雌性sd大鼠全膀胱，实验组动物在T9 ~ T10水平完全性脊髓横断，正常动物为对照组。纵向切开膀胱，切除三角区和尖端，将剩余组织修剪成每边9至13毫米的正方形。组织样品的力学性能测试采用平面双轴测试，其中在圆周和纵向（基底-顶点）方向施加应力，并测量由此产生的轴向应变。结果：在解剖方向上施加等应力时，正常大鼠和脊髓损伤大鼠膀胱壁组织表现出各向同性的力学行为。然而，在非等双轴载荷下，膀胱标本并不是真正的各向同性，而是表现出类似各向异性的行为。脊髓损伤组织始终比正常对照更具顺应性。结论：双轴力学试验可检测脊髓损伤后10、14天正常对照和肥大大鼠膀胱的差异。这些变化是膀胱对脊髓损伤反应的重要组成部分。
Purpose: Changes in the mechanical properties of the bladder wall after spinal cord injury can alter bladder compliance and wall tension, leading to changes in afferent nerve activity and to abnormal reflex mechanisms. To our knowledge we report the first application of biaxial mechanical testing to the normal bladder wall and demonstrate how these properties change after spinal cord injury.Materials and Methods: Whole bladders were harvested from mature female Sprague-Dawley rats weighing 250 to 300 gm, Test group animals underwent complete spinal cord transection at the T9 to T10 level and normal animals comprised the control group. The bladders were cut open longitudinally, the trigone and apex were removed and the remaining tissue was trimmed to a square of 9 to 13 mm. per side. Mechanical properties of the tissue sample were tested using planar biaxial testing, in which a stress was applied in the circumferential and longitudinal (base-apex) directions, and resulting axial strains were measured.Results: In normal and spinal cord injured rats bladder wall tissue demonstrated isotropic mechanical behavior when equal stress levels were applied in anatomical directions. However, under nonequi-biaxial loading bladder specimens were not truly isotropic but displayed anisotropic-like behavior. Spinal cord injured tissues were consistently more compliant than normal controls.Conclusions: Biaxial mechanical testing can detect differences in normal control and hypertrophied rat bladders 10 and 14 days after spinal cord injury. These changes represent an important component of the bladder response to spinal cord injury.