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

1.本研究从生长因子调控的胶原合成和代谢角度，采用原位冻融处理和自行建立的几种独特的动物模型，从生物力学和分子生物学的角度阐明了髌腱(PT)和前交叉韧带(ACL)组织的重塑现象。结果表明：(1)内源性成纤维细胞坏死对PT的力学性能无明显影响，但外源性成纤维细胞的渗入对PT的力学性能有影响。此外，应力剥夺和增强都显著恶化了原位冷冻前交叉韧带的力学性能。(2)在原位冷冻的PT中，第6周和第12周的外源性细胞中Ⅲ型前胶原基因过度表达，外源性细胞周围有III型胶原的表达。(3)应用IL-1β和PDGF-BB促进外源性成纤维细胞I-…胶原酶基因的表达而应用转化生长因子-β对其有抑制作用。(4)肌腱组织中的应力剥夺不仅导致成纤维细胞中IL-1β和转化生长因子-β的过度表达，而且降低了细胞外基质的力学性能。(5)冻融前交叉韧带在0周和3周应用小剂量的转化生长因子-β-1和表皮生长因子可抑制材料的破坏，但在6周应用相同剂量的转化生长因子-表皮生长因子并不能抑制材料的破坏。在每个时期，高剂量的应用都不能抑制它。(6)应用转化生长因子-β可改善前交叉韧带损伤后愈合组织的材料性能，而应用PDGF-BB对其无明显影响。此外，本研究还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，并利用生物力学和分子生物学的方法。在临床意义上，本研究提出了抑制移植肌腱和韧带组织材料性能恶化的治疗试验的基本原则，这是目前临床上的一个重要问题。我们相信，这一原则将有助于骨科外科和运动医学领域对损伤肌腱和韧带组织的基因治疗和基于组织工程的治疗的发展。较少

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