Effects of a cell-free method using collagen vitrigel incorporating TGF-1 on articular cartilage repair in a rabbit osteochondral defect model

We studied the ability of collagen vitrigel material to repair cartilage in vivo when used alone or with transforming growth factor-beta (TGF-beta). We measured the time course and quantity of TGF-1 released from the collagen vitrigel in vitro to quantify the controlled release of TGF-1. Over 14 days, 0.91 ng of TGF-beta was released from the collagen vitrigel. Osteochondral defects were made in the femoral trochlear groove in 36 Japanese white rabbits, which were divided into three groups: untreated group (group A), collagen vitrigel-implanted group (group B), and TGF-1-incorporated collagen vitrigel-implanted group (group C). The weight distribution ratio between the affected and unaffected limbs served as an indicator of pain. Animals were sacrificed at 4 and 12 weeks after surgery, and their tissues were assessed histologically. The weight distribution ratio increased in all groups and did not differ significantly between groups at 12 weeks. Group A needed 6 weeks to attain maximum improvement, and groups B and C showed near-maximum improvement at 4 and 2 weeks, respectively. The International Cartilage Repair Society II score improved significantly in group C relative to the other groups. These findings suggest that sustained, slow release of TGF-beta caused early pain mitigation and cartilage repair. (C) 2016 Wiley Periodicals, Inc.