Ghosh Payal, Stabley John N, Behnke Bradley J, Allen Matthew R, Delp Michael D
Department of Nutrition, Food and Exercise Science, Florida State University, Tallahassee, FL 32306, USA.
Sanford-Burnham Medical Research Institute, Orlando, FL 3282, USA.
Bone. 2016 Feb;83:156-161. doi: 10.1016/j.bone.2015.11.001. Epub 2015 Nov 9.
Spaceflight-induced remodeling of the skull is characterized by greater bone volume, mineral density, and mineral content. To further investigate the effects of spaceflight on other non-weight bearing bones of the head, as well as to gain insight into potential factors mediating the remodeling of the skull, the purpose of the present study was to determine the effects of spaceflight on mandibular bone properties. Female C57BL/6 mice were flown 15d on the STS-131 Space Shuttle mission (n=8) and 13d on the STS-135 mission (n=5) or remained as ground controls (GC). Upon landing, mandibles were collected and analyzed via micro-computed tomography for tissue mineralization, bone volume (BV/TV), and distance from the cemento-enamel junction to the alveolar crest (CEJ-AC). Mandibular mineralization was not different between spaceflight (SF) and GC mice for either the STS-131 or STS-135 missions. Mandibular BV/TV (combined cortical and trabecular bone) was lower in mandibles from SF mice on the STS-131 mission (80.7±0.8%) relative to that of GC (n=8) animals (84.2±1.2%), whereas BV/TV from STS-135 mice was not different from GC animals (n=7). The CEJ-AC distance was shorter in mandibles from STS-131 mice (0.217±0.004mm) compared to GC animals (0.283±0.009mm), indicating an anabolic (or anti-catabolic) effect of spaceflight, while CEJ-AC distance was similar between STS-135 and GC mice. These findings demonstrate that mandibular bones undergo skeletal changes during spaceflight and are susceptible to the effects of weightlessness. However, adaptation of the mandible to spaceflight is dissimilar to that of the cranium, at least in terms of changes in BV/TV.
航天飞行引起的颅骨重塑的特征是骨体积、矿物质密度和矿物质含量增加。为了进一步研究航天飞行对头部其他非承重骨骼的影响，并深入了解介导颅骨重塑的潜在因素，本研究的目的是确定航天飞行对下颌骨特性的影响。雌性C57BL/6小鼠在STS-131航天飞机任务中飞行15天（n = 8），在STS-135任务中飞行13天（n = 5），或作为地面对照（GC）。着陆后，收集下颌骨并通过微计算机断层扫描分析组织矿化、骨体积（BV/TV）以及从牙骨质-釉质交界到牙槽嵴的距离（CEJ-AC）。对于STS-131或STS-135任务，航天飞行（SF）小鼠和GC小鼠的下颌骨矿化没有差异。在STS-131任务中，SF小鼠下颌骨的BV/TV（皮质骨和小梁骨之和）低于GC（n = 8）动物（80.7±0.8%），而GC动物为（84.2±1.2%），而STS-135小鼠的BV/TV与GC动物（n = 7）没有差异。与GC动物（0.283±0.009mm）相比，STS-131小鼠下颌骨的CEJ-AC距离更短（0.217±0.004mm），表明航天飞行具有合成代谢（或抗分解代谢）作用，而STS-135小鼠和GC小鼠之间的CEJ-AC距离相似。这些发现表明，下颌骨在航天飞行期间会发生骨骼变化，并且易受失重影响。然而，下颌骨对航天飞行的适应性与颅骨不同，至少在BV/TV变化方面如此。
