Muscle-based gene therapy and tissue engineering for treatment of growth plate injuries

Growth plate injuries may lead to a progressive angular deformity or longitudinal growth disturbance. The authors investigated the feasibility of gene therapy and tissue engineering based on autologous muscle-and adenoviral-mediated gene transfer of insulin-like growth factor-1 (IGF-1) and bone morphogenetic protein-2 (BMP-2) to treat tibial physeal defects in rabbits. The medial half of the left proximal tibial growth plate was completely excised in 44 6-week-old New Zealand white rabbits. Four experimental groups were created: no treatment (I), autologous muscle interposition (II), autologous muscle interposition injected with adIGF-1 (III), and autologous muscle interposition injected with adBMP-2 (IV). Radiographic and histologic assessments were obtained postoperatively. Significant tibial shortening and a compact osseous bridge were observed in groups I and IV. Growth plates remained open in groups II and III. This experiment demonstrates that IGF-1 had a supportive effect on physeal chondrocytes, while BMP-2 caused increased osteogenic activity in the injured growth plates.