Orthopaedic Stem Cell Research Laboratory, Cedars-Sinai Medical Center (CSMC), Los Angeles, California, USA.
Board of Governors Regenerative Medicine Institute, CSMC, Los Angeles, California, USA.
J Orthop Res. 2024 Dec;42(12):2725-2734. doi: 10.1002/jor.25950. Epub 2024 Aug 6.
Secreted protein acidic and rich in cysteine (SPARC) is the most abundant glycoprotein in bone and is thought to play a critical role in bone remodeling and homeostasis. However, the effect of SPARC in relation to gender and exercise on bone quality is not well understood. The purpose of this study was to quantify differences in the structural and biomechanical properties between calvarial and femoral bone from male and female wild-type (WT) and SPARC null (SPARC) mice as well as the ability of exercise to rescue bone health. Male and female WT and transgenic SPARC mice were given either a fixed or rotating running wheel for exercise. Bone structural, biomechanical, and morphological parameters were quantified using micro computed tomography, push out testing for the calvaria, three-point flexural testing for the femurs, histological and immunofluorescent staining. Similar reductions in structural and biomechanical strength were observed in both male and female SPARC calvaria, most of which were not significantly affected by exercise. In femurs, SPARC had a significant effect on structural parameters in both sexes, but was more pronounced in females with some properties being rescued with running. Interestingly, the effect of SPARC on bone mineral density was only detected in female SPARC mice, not males, and was subsequently rescued with exercise. This study emphasizes the differences between sexes in WT and SPARC mice in regard to structural parameters and biomechanical properties. Research into gender differences can help inform and personalize treatment options to more accurately meet patient needs.
富含半胱氨酸的酸性分泌蛋白（SPARC）是骨骼中最丰富的糖蛋白，被认为在骨骼重塑和平衡中发挥着关键作用。然而，SPARC 与性别和运动对骨质量的影响尚不清楚。本研究的目的是定量分析雄性和雌性野生型（WT）和 SPARC 缺失（SPARC）小鼠颅骨和股骨在结构和生物力学特性方面的差异，以及运动对骨骼健康的恢复能力。雄性和雌性 WT 和转基因 SPARC 小鼠分别给予固定或旋转跑轮进行运动。使用微计算机断层扫描、颅骨推挤试验、股骨三点弯曲试验、组织学和免疫荧光染色来定量分析骨结构、生物力学和形态参数。SPARC 对雄性和雌性颅骨的结构和生物力学强度都有相似的降低作用，其中大部分不受运动的显著影响。在股骨中，SPARC 对两性的结构参数都有显著影响，但在雌性中更为明显，有些特性可以通过跑步来恢复。有趣的是，SPARC 对骨密度的影响仅在雌性 SPARC 小鼠中检测到，而在雄性中未检测到，随后通过运动得到恢复。本研究强调了 WT 和 SPARC 小鼠在结构参数和生物力学特性方面的性别差异。对性别差异的研究可以帮助提供个性化的治疗方案，更准确地满足患者的需求。
