IRCCS Ospedale Galeazzi Sant'Ambrogio, Via C. Belgioioso 173, 20161 Milan, Italy.
Department of Pharmacological and Biomedical Sciences "Rodolfo Paoletti", University of Milan, Via D. Trentacoste 2, 20134 Milan, Italy.
Cells. 2024 Mar 14;13(6):509. doi: 10.3390/cells13060509.
Gravity and mechanical forces cause important alterations in the human skeletal system, as demonstrated by space flights. Innovative animal models like zebrafish embryos and medaka have been introduced to study bone response in ground-based microgravity simulators. We used, for the first time, adult zebrafish in simulated microgravity, with a random positioning machine (RPM) to study bone remodeling in the scales. To evaluate the effects of microgravity on bone remodeling in adult bone tissue, we exposed adult zebrafish to microgravity for 14 days using RPM and we evaluated bone remodeling on explanted scales. Our data highlight bone resorption in scales in simulated microgravity fish but also in the fish exposed, in normal gravity, to the vibrations produced by the RPM. The osteoclast activation in both rotating and non-rotating samples suggest that prolonged vibrations exposure leads to bone resorption in the scales tissue. Stress levels in these fish were normal, as demonstrated by blood cortisol quantification. In conclusion, vibrational mechanical stress induced bone resorption in adult fish scales. Moreover, adult fish as an animal model for microgravity studies remains controversial since fish usually live in weightless conditions because of the buoyant force from water and do not constantly need to support their bodies against gravity.
重力和机械力会导致人体骨骼系统发生重要变化，这在太空飞行中得到了证明。创新的动物模型，如斑马鱼胚胎和青鳉，已被引入到地面微重力模拟器中研究骨骼的反应。我们首次在模拟微重力条件下使用成年斑马鱼，使用随机定位机（RPM）来研究鳞片中的骨骼重塑。为了评估微重力对成年骨骼组织中骨骼重塑的影响，我们使用 RPM 使成年斑马鱼暴露于微重力下 14 天，并评估了体外培养的鳞片中的骨骼重塑。我们的数据突出显示了模拟微重力条件下的骨吸收，但也显示了在正常重力下暴露于 RPM 产生的振动的鱼的骨吸收。旋转和非旋转样本中的破骨细胞激活表明，长时间的振动暴露会导致鳞片组织中的骨吸收。这些鱼的应激水平正常，这可以通过血液皮质醇定量来证明。总之，振动机械应激导致成年鱼鳞片的骨吸收。此外，成年鱼类作为微重力研究的动物模型仍然存在争议，因为鱼类通常由于水的浮力而处于失重状态，并且不需要不断地支撑身体对抗重力。
