Chair of Materials Science, Otto Schott Institute of Materials Research, Friedrich-Schiller-University Jena, Jena, Germany.
Chair of Orthopedics, Department of Orthopedics, Jena University Hospital, Waldkliniken Eisenberg GmbH, Eisenberg, Germany.
J Bone Miner Metab. 2020 Sep;38(5):620-630. doi: 10.1007/s00774-020-01098-x. Epub 2020 Apr 15.
Existing osteoporosis models in sheep exhibit some disadvantages, e.g., challenging surgical procedures, serious ethical concerns, failure of reliable induction of substantial bone loss, or lack of comparability to the human condition. This study aimed to compare bone morphological and mechanical properties of old and young sheep, and to evaluate the suitability of the old sheep as a model for senile osteopenia.
The lumbar vertebral body L3 of female merino sheep with two age ranges, i.e., old animals (6-10 years; n = 41) and young animals (2-4 years; n = 40), was analyzed concerning its morphological and mechanical properties by bone densitometry, quantitative histomorphometry, and biomechanical testing of the corticalis and/or central spongious region.
In comparison with young sheep, old animals showed only marginally diminished bone mineral density of the vertebral bodies, but significantly decreased structural (bone volume, - 15.1%; ventral cortical thickness, - 11.8%; lateral cortical thickness, - 12.2%) and bone formation parameters (osteoid volume, osteoid surface, osteoid thickness, osteoblast surface, all - 100.0%), as well as significantly increased bone erosion (eroded surface, osteoclast surface). This resulted in numerically decreased biomechanical properties (compressive strength; - 6.4%).
Old sheep may represent a suitable model of senile osteopenia with markedly diminished bone structure and formation, and substantially augmented bone erosion. The underlying physiological aging concept reduces challenging surgical procedures and ethical concerns and, due to complex alteration of different facets of bone turnover, may be well representative of the human condition.
现有的绵羊骨质疏松模型存在一些缺点，例如手术过程复杂、存在严重的伦理问题、难以可靠地诱导大量骨质流失，或者与人类状况缺乏可比性。本研究旨在比较老绵羊和年轻绵羊的骨骼形态和力学特性，并评估老绵羊作为老年骨质疏松症模型的适用性。
对两个年龄段的雌性美利奴绵羊的腰椎体 L3（老年动物，6-10 岁；n = 41；年轻动物，2-4 岁；n = 40）进行了骨密度测定、定量组织形态计量学和皮质和/或中央海绵状区域的生物力学测试，以分析其形态和力学特性。
与年轻绵羊相比，老年动物的椎体骨矿物质密度仅略有降低，但结构（骨体积，-15.1%；腹侧皮质厚度，-11.8%；外侧皮质厚度，-12.2%）和骨形成参数（类骨质体积、类骨质表面、类骨质厚度、成骨细胞表面，均为-100.0%）显著降低，同时骨吸收（吸收表面、破骨细胞表面）显著增加。这导致生物力学性能数值降低（抗压强度，-6.4%）。
老年绵羊可能是一种合适的老年骨质疏松症模型，具有明显降低的骨结构和形成，以及显著增加的骨吸收。其背后的生理衰老概念减少了具有挑战性的手术程序和伦理问题，并且由于骨转换的不同方面的复杂改变，可能更能代表人类状况。
