Integrated Analyses on adaptation and control mechanisms in remodeling of the extracellular matrix in the in situ frozen-thawed anterior cruciate ligament

1. 本研究从生物力学和分子生物学的角度，利用原位冻融处理和我们自己开发的几种独特的动物模型，从生长因子控制的胶原合成和代谢的角度阐明了髌腱（PT）和前交叉韧带（ACL）组织的重塑现象。结果表明：(1)至少在6周内，内源性成纤维细胞坏死对PT的力学性能没有显著影响，但外源性成纤维细胞浸润对PT的力学性能有影响。应力剥夺和应力增强均显著恶化原位冻结前交叉韧带的力学性能。(2)原位冷冻PT中，6周和12周外源性细胞中iii型前胶原mRNA过表达，外源性细胞周围有iii型胶原表达。(3)应用il -1 β和PDGF-BB可增强外源性成纤维细胞中胶原酶mRNA的表达，而应用tgf - β可抑制胶原酶mRNA的表达。(4)应力剥夺在肌腱组织中同时诱导成纤维细胞il -1 β和tgf - β的过度表达，并导致细胞外基质力学性能的降低。(5)低剂量TGF-β1和EGF分别作用于0周和3周的冻融前交叉韧带，对冻融后的材料变质有抑制作用，但相同剂量作用于6周时，对冻融后的材料变质无抑制作用。高剂量的应用并没有在每个时期抑制它。(6) tgf - β的应用改善了损伤前交叉韧带愈合组织的材料性能，而PDGF-BB的应用没有任何效果。此外，本研究利用生物力学和分子生物学方法，建立了一个新的综合分析系统，以阐明肌腱和韧带组织重塑的适应和控制机制。在临床意义上，本研究体现了治疗性试验的一个基本原则，即抑制移植肌腱和韧带组织材料性能的恶化，这是目前临床面临的一个重大问题。我们相信这一原理将有助于在骨科和运动医学领域对损伤肌腱和韧带组织进行基因治疗和组织工程治疗的发展。少

1. This study biomechanically and molecular-biologically clarified the remodeling phenomenon of the patellar tendon (PT) and anterior cruciate ligament (ACL) tissues from the viewpoint of collagen synthesis and metabolism controlled by growth factors, using the in situ freeze-thaw treatment and several unique animal models which were originally developed by us. The results were shown as follows : (1) Intrinsic fibroblast necrosis did not significantly affect the mechanical properties of the PT, at least, for 6 weeks, but extrinsic fibroblast infiltration affected them. In addition, both stress deprivation and enhancement significantly deteriorated the mechanical properties of the in situ frozen ACL. (2) In the situ frozen PT, type-III procollagen mRNA was overexpressed in the extrinsic cells at 6 and 12 weeks, and type-III collagen was expressed around the extrinsic cells. (3) Application of IL-1beta and PDGF-BB enhanced expression of the collagenase mRNA in the extrinsic fibroblasts i … More n the frozen PT, while application of TGF-beta inhibited it. (4) Stress deprivation in the tendon tissue simultaneously induced not only overexpression of IL-1beta and TGF-beta-in fibroblasts but also reduction of the mechanical properties of the extracellular matrix. (5) A low-dose of TGF-β1 and EGF applied to the frozen-thawed ACL at 0 and 3 weeks inhibitd the material deterioration caused by freezing, but the same dose application at 6 weeks did not inhibit it. A high dose application did not inhibit it at each period. (6) Application of TGF-beta improves the material properties of healing tissue in the injured ACL, but application of the PDGF-BB does not have any effects.2. In addition, this study established a new integrated analysis system to clarify adaptation and control mechanisms in remodeling of the tendon and ligament tissue, using the biomechanical and molecular-biological methods. As to clinical relevance, this study demonstrated a basic principle of therapeutic trials to inhibit the deterioration of the material properties of the grafted tendon and ligament tissues, which is a significant clinical problem at the present time. We believe that this principle will contribute development of gene therapy and tissue engineering-based treatment for the injured tendon and ligament tissues in the field of orthopaedic surgery and sports medicine. Less