Doctoral Dissertation: Collagen Fiber Orientation and Locomotor Loading in Primates

博士论文：灵长类动物的胶原纤维取向和运动负荷

• 批准号: 9910211
• 负责人: Owen Lovejoy
• 金额: $ 1.1万
• 依托单位: Kent State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-01-01 至 2000-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9910211&HistoricalAwards=false
• 关键词: Doctoral; Dissertation; Collagen; Fiber; Orientation

This study examines some important microscopic structural details of bone. Results can potentially improve our understanding of the tissue's microscopic architecture and how forces imposed on it during upright walking and running are distributed. Collagen fibers are a large component of bone microstructure. Their orientation reflects the types of forces sustained by bone over the time period during which it is being deposited. By microscopically analyzing histological sections, this study will provide new data about forces imposed on specific areas of the human skeleton during walking and running.Bone microstructure in animals that practice highly specialized forms of locomotion and which have been studied by other means such as in vivo strain gauge examination will first be reviewed. This will permit detailed standardization of methodology and also serve as a means of testing the capacity of collagen orientation to accurately reflect bone forces. It will then qualitatively and quantitatively assess the orientation of collagen fibers in human and non-human primate bone taken from highly localized parts of the skeleton. The first site to be studied will be the gibbon forelimb. Gibbons practice brachiation, which is a locomotor pattern in which the body is alternatively suspended by each forelimb. Strain in the gibbon ulna is primarily tensile, whereas, that in its companion bone of the forearm, the radius, is primarily bending. These force characteristics should specifically affect the collagen orientation in the two bones. This study will quantify and qualify the collagen fiber orientation in the gibbon forelimb and compare the results with the strains which have been measured in the limb. The second site that will be investigated in this study is the femoral necks of humans and chimpanzees. Human femoral necks are unique in that they have a very thin cortical bone shell at the superior portion. This region is very sensitive to bone loss from osteoporosis and is a frequent site of fracture in elderly females. An improved knowledge of the forces and structure of this region are therefore of potentially great importance. In contrast to those of humans, chimpanzee femoral necks are distinct because they have a thick cortical layer of bone on the superior neck. The different pattern of cortical bone development in humans and chimps is thought to be due to the forces sustained during their respective modes of locomotion and the result of different muscular anatomies in the hip. Humans practice bipedal locomotion during which the hip muscles function to stabilize the body on the pelvis, but chimpanzees only infrequently walk bipedally. The hip musculature in chimps therefore differs anatomically from that of humans. In humans the hip muscles (abductors) are thought to relieve forces on the upper part of the femoral neck. This results in only minimum bone formation in this region, and may be the primary reason for the thin cortical shell typical of human femora. However, chimp hip muscles do not have as strong an abductor function and therefore permit their femoral neck to suffer higher forces resulting in a thicker cortex. By examining collagen fiber orientation in chimp and human femoral necks, this study will determine what forces occur in the two species' femoral necks. These results will test whether the distribution of cortical bone is the result of different forces acting on the chimp and human femoral necks.This investigation will also examine the microanatomical construction of bone. The arrangement of collagen fibers in bone remains a highly debated topic in bone biology. Most researchers believe that collagen fibers possess particular orientations in bone. However, there are those who believe that collagen fibers are randomly oriented without any particular orientations. This study will examine collagen fibers in three orthogonal planes of bone in order to determine if specific orientations do indeed exist.The findings from this investigation will further our understanding of bone microstructure and its relationship to loads suffered by bone. This study will add critical new empirical evidence to the question of bone's microstructural adaptation to mechanical stimuli. In addition, new evidence will be produced that will help elucidate the microstructural architecture of bone by examining collagen fiber orientations. These results will have implications for physical anthropology, bone biology, orthopaedics, tissue engineering, and structural biology.

本研究检查了骨的一些重要的显微结构细节。这些结果可能会提高我们对组织微观结构的理解，以及在直立行走和跑步过程中施加在组织上的力是如何分布的。胶原纤维是骨微结构的主要组成部分。 它们的方向反映了骨在沉积期间所承受的力的类型。 通过显微镜分析组织切片，本研究将提供有关在行走和跑步过程中施加在人体骨骼特定区域上的力的新数据。首先，将回顾高度专业化运动形式的动物的骨骼微观结构，并通过其他手段进行研究，如体内应变仪检查。这将允许方法学的详细标准化，并且还用作测试胶原蛋白取向准确反映骨作用力的能力的手段。 然后，它将定性和定量地评估从骨骼的高度局部化部分获取的人类和非人类灵长类动物骨骼中胶原纤维的取向。 第一个研究的部位是腕关节前肢。 长臂猿练习臂动，这是一种运动模式，其中身体交替地悬挂在每个前肢上。 尺骨的应变主要是拉伸，而前臂的桡骨的应变主要是弯曲。 这些力的特征应该特别影响两块骨骼中的胶原蛋白方向。 本研究将定量和定性的胶原纤维的取向在gilobaly前肢和比较的结果与应变已被测量的肢体。 本研究将研究的第二个部位是人类和黑猩猩的股骨颈。 人类股骨颈的独特之处在于其在上级部分具有非常薄的皮质骨壳。该区域对骨质疏松引起的骨丢失非常敏感，是老年女性骨折的常见部位。因此，进一步了解这一地区的力量和结构具有潜在的重大意义。与人类的股骨颈不同，黑猩猩的股骨颈是独特的，因为它们的上级颈部有一层厚的骨皮质。 人类和黑猩猩皮质骨发育的不同模式被认为是由于其各自运动模式期间所承受的力以及臀部不同肌肉解剖结构的结果。 人类练习两足行走，在此过程中，臀部肌肉的功能是稳定身体在骨盆上，但黑猩猩很少用两足行走。 因此，黑猩猩的臀部肌肉组织在解剖学上与人类不同。 在人类中，臀部肌肉（外展肌）被认为是减轻股骨颈上部的力量。这导致在该区域仅形成最少的骨，并且可能是人类股骨典型的薄皮质壳的主要原因。 然而，黑猩猩的臀部肌肉没有强大的外展肌功能，因此允许他们的股骨颈承受更大的力量，导致更厚的皮质。 通过检测黑猩猩和人类股骨颈中的胶原纤维方向，这项研究将确定两个物种股骨颈中发生的力。 这些结果将检验黑猩猩和人类股骨颈上皮质骨的分布是否是不同作用力的结果，本研究还将检验骨的显微解剖结构。 骨中胶原纤维的排列在骨生物学中仍然是一个备受争议的话题。 大多数研究人员认为，胶原纤维在骨中具有特定的取向。 然而，有些人认为胶原纤维是随机取向的，没有任何特定的取向。 这项研究将检查骨骼三个正交平面中的胶原纤维，以确定是否确实存在特定的方向。这项研究的结果将进一步了解骨骼微观结构及其与骨骼所受载荷的关系。 这项研究将增加关键的新的经验证据的问题，骨的微观结构适应机械刺激。 此外，将产生新的证据，这将有助于阐明骨的微观结构架构，通过检查胶原纤维的方向。 这些结果将对体质人类学、骨生物学、骨科学、组织工程学和结构生物学产生影响。