1. Department of Orthopaedics, Xijing Hospital, Fourth Military Medical University, Xi'an, China;
Int J Med Sci. 2013 Oct 31;10(13):1805-16. doi: 10.7150/ijms.6530. eCollection 2013.
As a main cellular component within the disc, nucleus pulposus (NP) cells play important roles in disc physiology. However, little is known on the biologic hallmarks of human NP cells. Therefore, the present study aimed to address the features of human NP cells.
Human NP samples were collected from normal cadavers, patients with scoliosis and disc degeneration as normal, disease control and degenerative NP, respectively. The NP samples were studied using transmission electron microscopy and TUNEL assay. Pre-digested NP samples were studied using flow cytometry with PI/Annexin V staining.
Both control and degenerative human NP consisted of mainly viable cells with a variety of morphology. Both necrosis and apoptosis were noted in human NP as forms of cell death with increased apoptosis in degenerative NP, which was further confirmed by the TUNEL assay. Phagocytic NP cells had the hallmarks of both stationary macrophages with lysosomes and NP cells with the endoplasmic reticulum. Annulus fibrosus cells have similar morphologic characteristics with NP cells in terms of cell nest, phagocytosis and intracellular organs. Moreover, NP cells with long processes existed in degenerative and scoliotic NP rather than normal NP. When cultured in glucose-free medium, NP cells developed long and thin processes.
Human degenerative NP consists of primarily viable cells. We present direct and in vivo evidence that both human annulus fibrosus and NP cells have phagocytic potential. Moreover, NP cells with long processes exist in both scoliotic and degenerative NP with lack of glucose as one of the possible underlying mechanisms.
作为椎间盘的主要细胞成分，髓核细胞在椎间盘生理中发挥着重要作用。然而，人们对人髓核细胞的生物学特征知之甚少。因此，本研究旨在探讨人髓核细胞的特征。
从正常尸体、脊柱侧凸和椎间盘退变患者中分别采集正常椎间盘、疾病对照和退变髓核样本。通过透射电子显微镜和 TUNEL 检测研究 NP 样本。用 PI/Annexin V 染色对预消化的 NP 样本进行流式细胞术研究。
对照和退变的人 NP 均主要由具有多种形态的存活细胞组成。坏死和凋亡均见于人 NP 中，是细胞死亡的形式，退变 NP 中的凋亡增加，TUNEL 检测进一步证实了这一点。吞噬性 NP 细胞具有静止巨噬细胞的溶酶体和具有内质网的 NP 细胞的特征。纤维环细胞在细胞巢、吞噬作用和细胞内器官方面与 NP 细胞具有相似的形态特征。此外，在退变和脊柱侧凸的 NP 中存在具有长突起的 NP 细胞，而在正常 NP 中则不存在。在无糖培养基中培养时，NP 细胞会发育出长而细的突起。
人退变 NP 主要由存活细胞组成。我们提供了直接的体内证据，证明人纤维环和 NP 细胞均具有吞噬能力。此外，在缺乏葡萄糖的情况下，脊柱侧凸和退变的 NP 中存在具有长突起的 NP 细胞，这可能是其潜在机制之一。
