Early-Onset Degeneration of the lntervertebral Disc and Vertebral End Plate in Mice Deficient in Type IX Collagen.

The article presents a study on the prevalence and timeline of intervertebral disc degeneration in mice homozygous for an inactivated type IX collagen-knockout gene. The spine sections harvested from wild-type (WT) and type IX collagen-knockout mice at 3, 6, and 12 months of age were evaluated for evidence of histologic changes, by 2 blinded graders, using a semiquantitative grading method. The study found that there was evidence of more degeneration of the disc and end plate in the spines collagen-knockout mice compared with those of WT controls.