MechanoBiology Laboratory, Departments of Orthopaedic Surgery, Bioengineering, and Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA 15213, USA.
BMC Musculoskelet Disord. 2010 Jan 18;11:10. doi: 10.1186/1471-2474-11-10.
Tendons are traditionally thought to consist of tenocytes only, the resident cells of tendons; however, a recent study has demonstrated that human and mouse tendons also contain stem cells, referred to as tendon stem/progenitor cells (TSCs). However, the differential properties of TSCs and tenocytes remain largely undefined. This study aims to characterize the properties of these tendon cells derived from rabbits.
TSCs and tenocytes were isolated from patellar and Achilles tendons of rabbits. The differentiation potential and cell marker expression of the two types of cells were examined using histochemical, immunohistochemical, and qRT-PCR analysis as well as in vivo implantation. In addition, morphology, colony formation, and proliferation of TSCs and tenocytes were also compared.
It was found that TSCs were able to differentiate into adipocytes, chondrocytes, and osteocytes in vitro, and form tendon-like, cartilage-like, and bone-like tissues in vivo. In contrast, tenocytes had little such differentiation potential. Moreover, TSCs expressed the stem cell markers Oct-4, SSEA-4, and nucleostemin, whereas tenocytes expressed none of these markers. Morphologically, TSCs possessed smaller cell bodies and larger nuclei than ordinary tenocytes and had cobblestone-like morphology in confluent culture whereas tenocytes were highly elongated. TSCs also proliferated more quickly than tenocytes in culture. Additionally, TSCs from patellar tendons formed more numerous and larger colonies and proliferated more rapidly than TSCs from Achilles tendons.
TSCs exhibit distinct properties compared to tenocytes, including differences in cell marker expression, proliferative and differentiation potential, and cell morphology in culture. Future research should investigate the mechanobiology of TSCs and explore the possibility of using TSCs to more effectively repair or regenerate injured tendons.
传统上认为肌腱仅由肌腱细胞组成，即肌腱的固有细胞；然而，最近的一项研究表明，人和鼠的肌腱也含有干细胞，称为肌腱干/祖细胞（TSC）。然而，TSC 和肌腱细胞的差异特性在很大程度上仍未得到定义。本研究旨在表征源自兔肌腱的这些细胞的特性。
从兔的髌腱和跟腱中分离 TSC 和肌腱细胞。使用组织化学、免疫组织化学和 qRT-PCR 分析以及体内植入来检查两种细胞的分化潜能和细胞标志物表达。此外，还比较了 TSC 和肌腱细胞的形态、集落形成和增殖。
发现 TSC 能够在体外分化为脂肪细胞、软骨细胞和成骨细胞，并在体内形成肌腱样、软骨样和骨样组织。相比之下，肌腱细胞几乎没有这种分化潜能。此外，TSC 表达干细胞标志物 Oct-4、SSEA-4 和核干细胞，而肌腱细胞不表达这些标志物。形态上，TSC 比普通肌腱细胞具有更小的细胞体和更大的细胞核，在汇合培养时具有鹅卵石样形态，而肌腱细胞则高度拉长。TSC 在培养中也比肌腱细胞增殖更快。此外，髌腱来源的 TSC 形成的集落数量更多、更大，增殖速度比跟腱来源的 TSC 更快。
与肌腱细胞相比，TSC 表现出明显不同的特性，包括细胞标志物表达、增殖和分化潜能以及培养中的细胞形态的差异。未来的研究应该调查 TSC 的力学生物学，并探索使用 TSC 更有效地修复或再生受损肌腱的可能性。
