Altered Disc Mechanics in Mice Genetically Engineered for Reduced Type I Collagen

STUDY DESIGN: Mechanically test lumbar discs of transgenic mice in compression-tension and torsion. OBJECTIVES: Determine if a reduction in type I collagen results in decreased disc mechanics. SUMMARY OF BACKGROUND DATA: Quantitative relationships between disc structure and function would improve the understanding of disc generation and are essential relationships for functional tissue engineering. The reduced type I collagen transgenic mouse has been used in structure-function studies of bone and tendon, but not intervertebral discs. Methods for testing mouse discs have recently been developed, making disc structure-function studies possible. METHODS: Microradiographed and mechanically tested lumbar discs from control and collagen-reduced mice in both compression-tension and torsion were used. Disc area and polar moment of inertia were determined from radiographic data, stiffness…