据介绍，通常情况下，软骨的大小、形状和生物力学特性是由其大量的细胞外基质决定的。
与之相反，研究人员发现，多种小鼠软骨是由一种被称为脂软骨细胞的充满脂质的细胞构成的。尽管脂软骨细胞与脂肪细胞相似，但在分子层面上存在差异，且其脂质完全是通过从头脂肪生成途径产生的。因此，脂软骨细胞会生成大小均匀的脂滴，这些脂滴能够抵御全身性的脂质激增，而且在肥胖状态下也不会增大。脂软骨细胞还缺乏脂质动员因子，这使得其液泡具有出色的稳定性，能保护软骨在饥饿状态下不发生萎缩。
脂滴通过降低组织的刚度、强度和回弹性来调节脂软骨的生物力学特性。在包括人类在内的多种哺乳动物体内都发现了脂软骨细胞，但在非哺乳类四足动物体内却未发现。因此，就如同气泡包装膜一样，超级稳定的脂质液泡赋予了骨骼组织类似软骨的特性，而无需像 “泡沫包装材料” 那样的细胞外基质。
附：英文原文
Title: Superstable lipid vacuoles endow cartilage with its shape and biomechanics
Author: Raul Ramos, Kim T. Pham, Richard C. Prince, Leith B. Leiser-Miller, Maneeshi S. Prasad, Xiaojie Wang, Rachel C. Nordberg, Benjamin J. Bielajew, Jerry C. Hu, Kosuke Yamaga, Ji Won Oh, Tao Peng, Rupsa Datta, Aksana Astrowskaja, Axel A. Almet, John T. Burns, Yuchen Liu, Christian Fernando Guerrero-Juarez, Bryant Q. Tran, Yi-Lin Chu, Anh M. Nguyen, Tsai-Ching Hsi, Norman T.-L. Lim, Sandra Schoeniger, Ruiqi Liu, Yun-Ling Pai, Chella K. Vadivel, Sandy Ingleby, Andrew E. McKechnie, Frank van Breukelen, Kyle L. Hoehn, John J. RasweilerIV, Michinori Kohara, William J. Loughry, Scott H. Weldy, Raymond Cosper, Chao-Chun Yang, Sung-Jan Lin, Kimberly L. Cooper, Sharlene E. Santana, Jeffrey E. Bradley, Michael A. Kiebish, Michelle Digman, David E. James, Amy E. Merrill, Qing Nie, Thomas F. Schilling, Aliaksandr A. Astrowski, Eric O. Potma, Martín I. García-Castro, Kyriacos A. Athanasiou, Richard R. Behringer, Maksim V. Plikus
Issue&Volume: 2025-01-10
Abstract: Conventionally, the size, shape, and biomechanics of cartilages are determined by their voluminous extracellular matrix. By contrast, we found that multiple murine cartilages consist of lipid-filled cells called lipochondrocytes. Despite resembling adipocytes, lipochondrocytes were molecularly distinct and produced lipids exclusively through de novo lipogenesis. Consequently, lipochondrocytes grew uniform lipid droplets that resisted systemic lipid surges and did not enlarge upon obesity. Lipochondrocytes also lacked lipid mobilization factors, which enabled exceptional vacuole stability and protected cartilage from shrinking upon starvation. Lipid droplets modulated lipocartilage biomechanics by decreasing the tissue’s stiffness, strength, and resilience. Lipochondrocytes were found in multiple mammals, including humans, but not in nonmammalian tetrapods. Thus, analogous to bubble wrap, superstable lipid vacuoles confer skeletal tissue with cartilage-like properties without “packing foam–like” extracellular matrix.
DOI: ads9960
Source: https://www.science.org/doi/10.1126/science.ads9960