Effect of gender on bone turnover in adult rats during simulated weightlessness
Effect of gender on bone turnover in adult rats during simulated weightlessness
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DOI：
10.1152/japplphysiol.00455.2002
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发表时间：
2003-11-01
影响因子：
3.3
通讯作者：
Turner, RT
中科院分区：
文献类型：
--
作者：
Hefferan, TE;Evans, GL;Turner, RT
长时间的太空飞行会导致宇航员的骨质流失，但个体差异很大。这项大鼠研究的目的是确定性别是否会影响模拟失重期间的骨质流失。6月龄Fisher 344大鼠后肢去重2 wk后，用组织形态计量学方法评价近端胫骨。胫骨长度、骨面积、松质骨结构和骨形成存在性别差异。与雌性大鼠相比，雄性大鼠的胫骨长11.6%，皮质骨面积大27.8%，骨小梁分离大37.6%。相反，雌性大鼠的皮质骨（316%）和松质骨（145%）形成率更高，松质骨多28.6%，小梁数量多30%。后肢减重导致两种性别的骨膜骨形成和矿物质沉积率大幅降低。减重也导致两种性别的松质骨丢失;骨小梁数量减少，骨小梁分离增加。然而，两种性别的骨小梁厚度均无变化。松质骨的这些结构变化与骨形成和骨基质蛋白和松质骨吸收的稳态mRNA水平降低有关。总之，骨量和转换存在主要的性别相关差异;然而，后肢未称重成年雄性和雌性大鼠的骨丢失似乎是由于相似的机制所致。
Prolonged spaceflight results in bone loss in astronauts, but there is considerable individual variation. The goal of this rat study was to determine whether gender influences bone loss during simulated weightlessness. Six-month-old Fisher 344 rats were hindlimb unweighted for 2 wk, after which the proximal tibiae were evaluated by histomorphometry. There were gender differences in tibia length, bone area, cancellous bone architecture, and bone formation. Compared with female rats, male rats had an 11.6% longer tibiae, a 27.8% greater cortical bone area, and a 37.6% greater trabecular separation. Conversely, female rats had greater cortical (316%) and cancellous (145%) bone formation rates, 28.6% more cancellous bone, and 30% greater trabecular number. Hindlimb unweighting resulted in large reductions in periosteal bone formation and mineral apposition rate in both genders. Unweighting also caused cancellous bone loss in both genders; trabecular number was decreased, and trabecular separation was increased. There was, however, no change in trabecular thickness in either gender. These architectural changes in cancellous bone were associated with decreases in bone formation and steady-state mRNA levels for bone matrix proteins and cancellous bone resorption. In conclusion, there are major gender-related differences in bone mass and turnover; however, the bone loss in hindlimb unweighted adult male and female rats appears to be due to similar mechanisms.