Figure 4: Mkx−/− mice develop early onset disc degeneration.

(a,b) Histological and computerized tomography (CT) changes with age between Mkx+/+ and Mkx−/− mice. Safranin O fast green staining of sagittal sections of L3/4 (a) and sagittal CT images of the lumbar spine (b) at 10 weeks, and 6, 12 and 21 months. Scale bars, 300 μm. (c) Histological degenerative scores of intervertebral discs (IVDs) in Mkx+/+ and Mkx−/− mice. Error bars represent s.e.m. **P<0.01, ***P<0.001. Statistical differences were assessed with Student’s t-test.