Fig. 4

Differentiation of hypertrophic chondrocytes within the central region of growth plates was impaired in Mapk7 CKO mice. a EdU labeling-chasing assay and corresponding HE staining of tibial sections from P4 mice. Dotted lines areas represent the proliferative zone and hypertrophic zone. PZ: proliferative zone; HZ: hypertrophic zone. b Quantification of EdU-positive cells in proliferative and hypertrophic zone. The percentage means EdU-labeled in hypertrophic zone relative to total number of EdU-positive chondrocytes in the proliferative and hypertrophic zone. HCs, hypertrophic chondrocytes. (n = 5) *P < 0.05 (Student’s t test). Data are presented as mean ± SD. c Real-time quantitative PCR was performed to measure Col10a1, Mmp13, Runx2, Opn, and Ihh mRNA expression levels in growth plates from P1 mice (n = 3). *P < 0.05 (Student’s t test). Data are presented as mean ± SD. d Protein levels of MAPK7, COL10A1, MMP13, RUNX2, and IHH in growth plates isolated from CON and Mapk7 CKO mice at P1 were assayed by western blot. e–g, i Immunofluorescence staining of (e) RUNX2, (f) COL10A1, (g) MMP13, and (i) OSX on representative sections of proximal tibial growth plates from P1 mice. Boxed areas are magnified in the images at the bottom. h Von Kossa staining of proximal tibial growth plates. Boxed areas are magnified in the images at the bottom. Scale bar, 200 μm