Research concerning articular cartilage repair using novel growth factor

AG-041R是一种胆囊收缩素-B/胃泌素受体拮抗剂，最初是为治疗胃溃疡而开发的。在大鼠的临床前毒理学研究中，发现大剂量口服AG-041R可刺激包括关节软骨在内的全身性软骨增生。本研究的第一个目的是探索关节软骨局部给药的方法。将不同量的AG-01R与不同种类的PL(G)A混合制成多种微球，并将含胶原蛋白的微球植入兔全厚关节软骨5 mm直径缺损处。几周后处死兔，用高效液相色谱法测定滑液和修复组织中AG-041R的含量。我们可以证实，含有40%AG-04R的PLA0020微球在修复组织中保留了4周，我们认为这是理想的时间段。第二个目的是验证FAG-041R修复关节软骨的有效性并对其进行组织学检查。将胶原凝胶与含40%的聚乳酸微球0.5 mg或2.5 mg混合，作为实验组，将胶原凝胶与等量的聚乳酸微球混合，作为对照组。移植后4、8、12周取材，行组织学检查、组织学检查及免疫组织化学染色。术后12周，实验组植入含40%聚乳酸微球2.5 mg，修复良好，II型胶原染色阳性，I型胶原染色阴性，BrdU染色检测细胞增殖，TUNEL染色检测细胞凋亡，为进一步的组织学检查奠定基础。

AG-041R is a cholecystokinin-B/gastrin receptor antagonist, which was originally developed to treat gastric ulcers. In a preclinical toxicological study on rats, oral administration of a high dose of AG-041R was found to stimulate systemic cartilage hyperplasia, including the articular cartilage.1 ; The first aim of this study is to develop the way of local administration for articular cartilage.PDLLA microspheres containing AG-041R were prepared by the solvent-evaporation method. Many kinds of microspheres was made by mixing various amounts of AG-01R and various kinds of PL(G)A. We indeed implanted the collagen containing microsphere into the 5 mm-diameter full-thickness articular cartilage defect of rabbit patellar groove. After certain weeks, we sacrificed the rabbit and measure the AG-041R content in synovial fluid and reparative tissue by HPLC. We could confirm that PLA0020 microsphere containing 40% AG-04R remained in reparative tissue for 4 weeks, which we thought ideal periods.2 ; The second aim is to verify the effectiveness ofAG-041R for articular cartilage repair and to examine it histologically.We made the same cartilage defect as above in both knee. Collagen gel mixed with 0.5 or 2.5mg PLA microspheres containing 40% were implanted into the left knee, as experimental group, and collagen gel mixed with same volume of just PLA microsphere, as control group. 4, 8, 12 weeks after implantation, reparative tissues were examined histologically by Toluidin Blue and immunofistochemistoly of type I and II collagen. 12 weeks after implantation, the reparative tissues of experimental group implanted with 2.5mg PLA microspheres containing 40 % were well repaired and the tissue were confined type II collagen positive and type I collagen negative.As future direction, we planed the more detailed histologically examination by BrdU stain for proliferating cell and TUNEL stain for apoptosis.