Swelling is the primary load-bearing mechanism in both nondegenerate and degenerate nucleus pulposus. Knowledge of the biphasic material properties of the nucleus pulposus will aid the development of new treatment strategies for disc degeneration aimed at restoring mechanical function of the intervertebral disc.

Results from this study suggest that T1rho may provide a tool for the diagnosis of early degenerative changes in the disc. T1rho-weighted MRI is a noninvasive technique that may provide higher dynamic range than T2 and does not require a high static field or exogenous contrast agents.

A needle puncture may directly alter mechanical properties via nucleus pulposus depressurization and/or anulus fibrosus damage, depending on the relative needle size. As more basic science research is aimed at treating disc degeneration via injection of therapeutic factors, these findings provide guidance in design of animal studies. Such studies should consider the relative needle size and include sham control groups to account for the potential effects of the needle injection.