Goodrich L R, Hidaka C, Robbins P D, Evans C H, Nixon A J
Colorado State University, College of Veterinary Medicine, Fort Collins, Colorado 80523, USA.
J Bone Joint Surg Br. 2007 May;89(5):672-85. doi: 10.1302/0301-620X.89B5.18343.
Gene therapy with insulin-like growth factor-1 (IGF-1) increases matrix production and enhances chondrocyte proliferation and survival in vitro. The purpose of this study was to determine whether arthroscopically-grafted chondrocytes genetically modified by an adenovirus vector encoding equine IGF-1 (AdIGF-1) would have a beneficial effect on cartilage healing in an equine femoropatellar joint model. A total of 16 horses underwent arthroscopic repair of a single 15 mm cartilage defect in each femoropatellar joint. One joint received 2 x 10(7) AdIGF-1 modified chondrocytes and the contralateral joint received 2 x 10(7) naive (unmodified) chondrocytes. Repairs were analysed at four weeks, nine weeks and eight months after surgery. Morphological and histological appearance, IGF-1 and collagen type II gene expression (polymerase chain reaction, in situ hybridisation and immunohistochemistry), collagen type II content (cyanogen bromide and sodium dodecyl sulphate-polyacrylamide gel electrophoresis), proteoglycan content (dimethylmethylene blue assay), and gene expression for collagen type I, matrix metalloproteinase (MMP)-1, MMP-3, MMP-13, aggrecanase-1, tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) and TIMP-3 were evaluated. Genetic modification of chondrocytes significantly increased IGF-1 mRNA and ligand production in repair tissue for up to nine weeks following transplantation. The gross and histological appearance of IGF-1 modified repair tissue was improved over control defects. Gross filling of defects was significantly improved at four weeks, and a more hyaline-like tissue covered the lesions at eight months. Histological outcome at four and nine weeks post-transplantation revealed greater tissue filling of defects transplanted with genetically modified chondrocytes, whereas repair tissue in control defects was thin and irregular and more fibrous. Collagen type II expression in IGF-1 gene-transduced defects was increased 100-fold at four weeks and correlated with increased collagen type II immunoreaction up to eight months. Genetic modification of chondrocytes with AdIGF-1 prior to transplantation improved early (four to nine weeks), and to a lesser degree long-term, cartilage healing in the equine model. The equine model of cartilage healing closely resembles human clinical cartilage repair. The results of this study suggest that cartilage healing can be enhanced through genetic modification of chondrocytes prior to transplantation.
胰岛素样生长因子-1（IGF-1）基因治疗可增加基质生成，并在体外增强软骨细胞的增殖和存活。本研究的目的是确定经编码马IGF-1的腺病毒载体（AdIGF-1）基因修饰的关节镜下移植软骨细胞是否会对马股髌关节模型中的软骨愈合产生有益影响。总共16匹马接受了每个股髌关节单个15毫米软骨缺损的关节镜修复。一个关节接受2×10⁷个经AdIGF-1修饰的软骨细胞，对侧关节接受2×10⁷个未处理（未修饰）的软骨细胞。在手术后4周、9周和8个月对修复情况进行分析。评估了形态学和组织学外观、IGF-1和II型胶原基因表达（聚合酶链反应、原位杂交和免疫组织化学）、II型胶原含量（溴化氰和十二烷基硫酸钠-聚丙烯酰胺凝胶电泳）、蛋白聚糖含量（二甲基亚甲基蓝测定法）以及I型胶原、基质金属蛋白酶（MMP）-1、MMP-3、MMP-13、聚集蛋白聚糖酶-1、基质金属蛋白酶组织抑制剂-1（TIMP-1）和TIMP-3的基因表达。软骨细胞的基因修饰在移植后长达9周内显著增加了修复组织中IGF-1 mRNA和配体的产生。与对照缺损相比，IGF-1修饰的修复组织的大体和组织学外观得到改善。缺损的大体填充在4周时显著改善，8个月时病变处覆盖有更类似透明软骨的组织。移植后4周和9周的组织学结果显示，经基因修饰的软骨细胞移植的缺损处组织填充更多，而对照缺损处的修复组织薄且不规则，纤维更多。IGF-1基因转导缺损处的II型胶原表达在4周时增加了100倍，并与直至8个月时II型胶原免疫反应的增加相关。移植前用AdIGF-1对软骨细胞进行基因修饰改善了马模型中早期（4至9周）以及程度较轻的长期软骨愈合。软骨愈合的马模型与人类临床软骨修复非常相似。本研究结果表明，移植前对软骨细胞进行基因修饰可增强软骨愈合。
