It is hard to explain the decrease in mechanosensitivity of osteocytes under microgravity. Primary cilia are essential mechanosensor for osteocytes. The cilia become shorter under the simulated microgravity (SMG) environment. The cilia change may be the reason for the mechanosensitivity decrease of osteocytes under SMG. To reveal the role of primary cilia in weightless-induced osteocyte dysfunction, we investigate intraflagellar transport (IFT) to understand the mechanism of the decreased cilia length of osteocytes when subjected to SMG. We measure the number of anterograde IFT particles with GFP::IFT88 and retrograde IFT particles with OFP::IFT43 that occur at a particular transverse plane of the cilia. We also measure the expression of IFT88 and IFT43 and the size of IFT particles under SMG. Herein, the ratio of anterograde/retrograde particle number and the ratio of protein expression of IFT88/IFT43 increase under SMG. The size of anterograde IFT particles with GFP::IFT88 gets a significant decrease under SMG. Fundamentally, SMG has broken the balanced operating state of IFT and makes the IFT particles smaller. The phenomenon under SMG is intriguing.

很难解释微重力作用下骨细胞机械敏感性的降低。原发纤毛是骨细胞必不可少的机械传感器。在模拟微重力（SMG）环境下，纤毛会变短。纤毛变化可能是SMG下骨细胞机械敏感性降低的原因。为了揭示原发性纤毛在失重诱导的骨细胞功能障碍中的作用，我们调查鞭毛内运输（IFT），以了解接受SMG时纤毛长度减少的机制。我们用GFP :: IFT88测量顺行IFT粒子的数量，用OFP :: IFT43逆行IFT粒子的数量发生在纤毛的特定横向平面上。我们还测量了SMG下IFT88和IFT43的表达以及IFT颗粒的大小。在这里 SMG作用下，逆行/逆行粒子数之比和IFT88 / IFT43蛋白表达之比增加。在SMG下，带有GFP :: IFT88的顺行IFT粒子的尺寸显着减小。从根本上说，SMG打破了IFT的平衡运行状态，并使IFT颗粒变小。SMG下的现象很有趣。