Li Jun, Liu Chen, Guo Qianping, Yang Huilin, Li Bin
Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China.
Orthopedic Institute, Soochow University, Suzhou, Jiangsu, China.
PLoS One. 2014 Mar 12;9(3):e91799. doi: 10.1371/journal.pone.0091799. eCollection 2014.
Tissue engineering of annulus fibrosus (AF), the essential load-bearing disc component, remains challenging due to the intrinsic heterogeneity of AF tissue. In order to provide a set of characterization data of AF tissue, which serve as the benchmark for constructing tissue engineered AF, we analyzed tissues and cells from various radial zones of AF, i.e., inner AF (iAF), middle AF (mAF), and outer AF (oAF), using a rabbit model. We found that a radial gradient in the cellular, biochemical, and biomechanical characteristics of rabbit AF existed. Specifically, the iAF cells (iAFCs) had the highest expression of collagen-II and aggrecan genes, while oAF cells (oAFCs) had the highest collagen-I gene expression. The contents of DNA, total collagen and collagen-I sequentially increased from iAF, mAF to oAF, while glycosaminoglycan (GAG) and collagen-II levels decreased. The cell traction forces of primary AFCs gradually decreased from iAFCs, mAFCs to oAFCs, being 336.6±155.3, 199.0±158.8, and 123.8±76.1 Pa, respectively. The storage moduli of iAF, mAF, and oAF were 0.032±0.002, 2.121±0.656, and 4.130±0.159 MPa, respectively. These measurements have established a set of reference data for functional evaluation of the efficacy of AF tissue engineering strategies using a convenient and cost-effective rabbit model, the findings of which may be further translated to human research.
纤维环（AF）是椎间盘的主要承重部件，由于其固有的异质性，其组织工程仍然具有挑战性。为了提供一组AF组织的表征数据，作为构建组织工程化AF的基准，我们使用兔模型分析了AF不同径向区域的组织和细胞，即内AF（iAF）、中AF（mAF）和外AF（oAF）。我们发现兔AF在细胞、生化和生物力学特性方面存在径向梯度。具体而言，iAF细胞（iAFCs）中胶原蛋白II和聚集蛋白聚糖基因的表达最高，而oAF细胞（oAFCs）中胶原蛋白I基因的表达最高。DNA、总胶原蛋白和胶原蛋白I的含量从iAF、mAF到oAF依次增加，而糖胺聚糖（GAG）和胶原蛋白II的水平则下降。原代AFCs的细胞牵引力从iAFCs、mAFCs到oAFCs逐渐降低，分别为336.6±155.3、199.0±158.8和123.8±76.1 Pa。iAF、mAF和oAF的储能模量分别为0.032±0.002、2.121±0.656和4.130±0.159 MPa。这些测量为使用方便且经济高效的兔模型对AF组织工程策略的疗效进行功能评估建立了一组参考数据，其结果可能会进一步转化为人体研究。
