Objective: To clarify the structure and biomechanical characteristics of the dura mater of the cervical, thoracic, and lumbar segments of sheep, in order to provide a theoretical reference for the study of artificial dura mater.
Methods: Five adult male white sheep were sacrificed. The dura mater of C 5, T 10, and L 3 planes were obtained. The histological HE staining was used to observe the internal structure and the thickness of dura mater; the inner and outer surfaces morphology of the dura was observed by scanning electron microscopy (SEM); transmission electron microscopy (TEM) was used to observe the internal structure of dura mater and to measure the diameter of collagen fibers in each part of dura mater. The dura mater of C 6, C 7, T 11, T 12, L 4, and L 5 planes were taken for uniaxial biomechanical test, and modulus of elasticity, tensile strength, and elongation at break were measured.
Results: HE staining showed that the thickness of the cervical, thoracic, and lumbar dura mater gradually decreased, and the thickness of the dura mater was (268.19±15.91), (198.16±27.25), (103.74±21.54) μm, respectively, and the differences were significant ( P<0.05). SEM observation showed that there were more collagen fibers and fewer cells on the inner surface of the dura mater, while more cells were distributed on the outer surface, and the cells on the inner and outer surface were stretched along the longitudinal axis. TEM observation showed that the collagen fibers in the dura mater were interlaced and arranged in layers. The collagen fibers in the lamina were arranged in the same direction, and the collagen fibers between the lamina were arranged vertically. The diameters of collagen fibers in the cervical, thoracic, and lumbar dura mater were (68.04±21.00), (64.54±20.64), (60.36±19.65) nm, respectively, and the differences were not significant ( P>0.05). Uniaxial biomechanical tests results showed that there was no significant difference in modulus of elasticity, tensile strength, and elongation at break between the axial and transverse dura mater of the cervical dura mater ( P>0.05); the axial data of thoracic and lumbar segments were significantly larger than the transverse data ( P<0.05). The axial modulus of elasticity, tensile strength, and elongation at break of the dura mater of the cervical, thoracic, and lumbar dura mater were significantly different ( P<0.05) from the transverse ones, and showing a decreasing trend. Among them, the ratio of axial and transverse modulus of elasticity of cervical and thoracic dura were significantly smaller than that of lumbar segment ( P<0.05), and there was no significant difference between cervical segments and thoracic segments ( P>0.05).
Conclusion: The thickness of dura mater in sheep decreased gradually from head to tail. There are more collagen fibers and fewer cells on the inner surface of dura mater, while the outer surface of dura mater is covered by cells. The collagen fiberboard layers in the dura mater are arranged alternately, and have obvious anisotropic biomechanical characteristics, and the anisotropic biomechanical characteristics get more significant from the head to the tail.
目的: 了解绵羊颈、胸、腰段硬脊膜的结构和生物力学特点，为人工硬脊膜的研发提供理论参考。.
方法: 取 5 只成年雄性白绵羊，处死后取 C 5、T 10 和 L 3 平面的硬脊膜分别行组织学 HE 染色观察内部结构并测量硬脊膜厚度，扫描电镜观察硬脊膜内外表面形态，透射电镜观察硬脊膜内部结构并测量各部位硬脊膜胶原纤维直径。取 C 6、C 7、T 11、T 12、L 4、L 5 平面的硬脊膜行单轴生物力学测试，测量样本的断裂强度、弹性模量和断裂伸长率。.
结果: HE 染色示颈、胸、腰段硬脊膜厚度逐渐递减，分别为（268.19±15.91）、（198.16±27.25）、（103.74±21.54）μm，比较差异均有统计学意义（ P<0.05）。扫描电镜观察示，硬脊膜内表面胶原纤维较多，细胞较少；外表面则细胞分布较多，且细胞均沿纵轴方向拉伸。透射电镜观察示，硬脊膜内部胶原纤维板层状交织排列，板层内胶原纤维同向排列，板层间胶原纤维相互垂直。颈、胸、腰段硬脊膜胶原纤维直径分别为（68.04±21.00）、（64.54±20.64）、（60.36±19.65）nm，比较差异无统计学意义（ P>0.05）。单轴生物力学测试显示，颈段硬脊膜轴向和横向的弹性模量、断裂强度、断裂伸长率比较差异均无统计学意义（ P>0.05）；胸段和腰段轴向各指标均显著大于横向（ P<0.05）。组间比较：颈、胸、腰段硬脊膜的轴向和横向弹性模量、断裂强度、断裂伸长率，两两比较差异均有统计学意义（ P<0.05），呈颈、胸、腰段逐渐减小趋势。颈、胸段硬脊膜轴向弹性模量与横向弹性模量比值显著小于腰段（ P<0.05）；颈、胸段间比较差异无统计学意义（ P>0.05）。.
结论: 绵羊硬脊膜从头侧向尾侧厚度依次减小；硬脊膜内表面胶原纤维分布较多、细胞较少，而外表面被细胞覆盖；硬脊膜内部胶原纤维板层交替排列，具有明显的各向异性生物力学特点，且从头侧向尾侧各向异性生物力学特点越明显。.
Keywords: Dura mater; mechanical characteristics; sheep; structure.