Zhao Jingbo, Liao Donghua, Chen Pengmin, Kunwald Peter, Gregersen Hans
Mech-Sense, Aalborg Hospital Science and Innovation Centre (AHSIC), Aalborg Hospital, Søndre Skovvej 15, DK-9000 Aalborg, Denmark.
J Biomech. 2008 Dec 5;41(16):3441-7. doi: 10.1016/j.jbiomech.2008.09.008. Epub 2008 Nov 11.
The stomach is as other parts of the gastrointestinal tract functionally subjected to dimensional change. Hence, the biomechanical properties are of functional importance. Our group has previously demonstrated that the stress-strain properties of the rat and rabbit stomach wall were species-, location- and direction-dependent. We further wanted to study the anisotropic biomechanical properties of the stomach wall in pigs. Furthermore, we made an in-depth biomechanical test on the layered wall of the stomach in different regions. Two stomach strips were cut both in longitudinal direction (parallel with the greater curvature) and circumferential direction (perpendicular to the greater curvature) from the gastric fundus, corpus and antrum. One strip was used for the non-separated (intact) wall test and the other one was separated for the test on the mucosa-submucosa and muscle layers individually. The length, thickness and width of each strip were measured from digital images. The uni-axial stress and strain were computed from the force generation and the tissue strip deformation during stretching. The muscle layer was the thickest in the antrum whereas the mucosal-submucosal layer was the thickest in the corpus of the stomach (P<0.01). The strips from the corpus were stiffest among the three regions in both longitudinal and circumferential directions (P<0.001). The longitudinal strips was stiffer than the circumferential strips in all three regions (P<0.001) and the mucosa-submucosa strips was stiffer than the intact wall and the muscle layer in both directions for the fundus and the corpus (P<0.001). The constant a of the intact wall and mucosa-submucosa layer was in both directions linearly associated with the mucosa-submucosa thickness. In conclusion, the uni-axial stress-strain curves of pig stomach were location-, direction- and layer-dependent. The stiffer wall in the corpus is likely due to its thicker mucosa, i.e., the stiffness of the mucosa-submucosa layer seems can explain the intact wall stiffness. Since the structure and function of the pig stomach are similar to the human stomach, we believe that the data obtained from this study can be extended to humans. Detailed biomechanical mapping of the stomach will likely help us to understand physiological functions of the different parts of the human stomach, such as gastric accommodation and mechanosensation.
胃与胃肠道的其他部分一样，在功能上会发生尺寸变化。因此，生物力学特性具有重要的功能意义。我们的研究小组之前已经证明，大鼠和兔胃壁的应力应变特性具有物种、位置和方向依赖性。我们进一步希望研究猪胃壁的各向异性生物力学特性。此外，我们对胃不同区域的分层壁进行了深入的生物力学测试。从胃底、胃体和胃窦纵向（平行于大弯）和周向（垂直于大弯）切取两条胃条。一条用于非分离（完整）壁测试，另一条分离后分别用于黏膜-黏膜下层和肌层测试。每条胃条的长度、厚度和宽度通过数字图像测量。单轴应力和应变通过拉伸过程中的力产生和组织条变形计算得出。肌层在胃窦最厚，而黏膜-黏膜下层在胃体最厚（P<0.01）。在纵向和周向，来自胃体的胃条在三个区域中最硬（P<0.001）。在所有三个区域，纵向胃条比周向胃条更硬（P<0.001），并且在胃底和胃体的两个方向上，黏膜-黏膜下层胃条比完整壁和肌层更硬（P<0.001）。完整壁和黏膜-黏膜下层的常数a在两个方向上都与黏膜-黏膜下层厚度呈线性相关。总之，猪胃的单轴应力应变曲线具有位置、方向和层依赖性。胃体壁更硬可能是由于其黏膜更厚，即黏膜-黏膜下层的硬度似乎可以解释完整壁的硬度。由于猪胃的结构和功能与人类胃相似，我们认为从本研究中获得的数据可以推广到人类。对胃进行详细的生物力学测绘可能有助于我们理解人类胃不同部分的生理功能，如胃容纳和机械感觉。
