Farnum C E, Turgai J, Wilsman N J
College of Veterinary Medicine, Cornell University, Ithaca, New York 14853.
J Orthop Res. 1990 Sep;8(5):750-63. doi: 10.1002/jor.1100080517.
The functional unit within the growth plate consists of a column of chondrocytes that passes through a sequence of phases including proliferation, hypertrophy, and death. It is important to our understanding of the biology of the growth plate to determine if distal hypertrophic cells are viable, highly differentiated cells with the potential of actively controlling terminal events of endochondral ossification prior to their death at the chondro-osseous junction. This study for the first time reports on the visualization of living hypertrophic chondrocytes in situ, including the terminal hypertrophic chondrocyte. Chondrocytes in growth plate explants are visualized using rectified differential interference contrast microscopy. We record and measure, using time-lapse cinematography, the rate of movement of subcellular organelles at the limit of resolution of this light microscopy system. Control experiments to assess viability of hypertrophic chondrocytes include coincubating organ cultures with the intravital dye fluorescein diacetate to assess the integrity of the plasma membrane and cytoplasmic esterases. In this system, all hypertrophic chondrocytes, including the very terminal chondrocyte, exist as rounded, fully hydrated cells. By the criteria of intravital dye staining and organelle movement, distal hypertrophic chondrocytes are identical to chondrocytes in the proliferative and early hypertrophic cell zones.
生长板内的功能单位由一列软骨细胞组成，这些软骨细胞会经历一系列阶段，包括增殖、肥大和死亡。确定远端肥大细胞是否为存活的、高度分化的细胞，在软骨 - 骨交界处死亡之前是否具有主动控制软骨内骨化终末事件的潜力，对于我们理解生长板生物学至关重要。本研究首次报道了原位活肥大软骨细胞的可视化，包括终末肥大软骨细胞。使用校正后的微分干涉相差显微镜观察生长板外植体中的软骨细胞。我们使用延时摄影在该光学显微镜系统的分辨率极限下记录和测量亚细胞器的移动速率。评估肥大软骨细胞活力的对照实验包括将器官培养物与活体染料荧光素二乙酸酯共同孵育，以评估质膜和细胞质酯酶的完整性。在这个系统中，所有肥大软骨细胞，包括最末端的软骨细胞，均以圆形、完全水合的细胞形式存在。根据活体染料染色和细胞器移动的标准，远端肥大软骨细胞与增殖区和早期肥大细胞区的软骨细胞相同。
