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. 2014 May 29;10(5):e1004364. doi: 10.1371/journal.pgen.1004364

Figure 6. Disordered maturation zones and delayed terminal differentiation in mouse vertebral growth plates following mosaic postnatal inactivation of Ptpn11 in chondrocytes.

Figure 6

Immunohistochemistry performed on tissue sections from the vertebral growth plates of Ctrl mice (A,D) or the growth plates (B,E) or enchondroma-like lesions (C) in Col2a1-cKO mice. A: Ctrl growth plate showing COLX, p-ERK1/2 and FRA1 immunoreactivity in the hypertrophic zone. COLX immunoreactivity is also observed in the calcifying region of the annulus fibrosus that lies directly above the growth plate. B: Col2a1-cKO growth plate showing ectopic COLX-positive clusters at the top of the growth plate (a) and ectopic COLX-negative clusters at the bottom of the growth plate (b). Furthermore, hypertrophic chondrocytes within the center of the growth plate display disorganized, scattered p-ERK1/2 and FRA1 immunoreactivity (c). C: Enchondroma-like lesions contain both COLX-positive and COLX-negative chondrocytes. D: Ctrl growth plate showing SPP1 immunoreactivity at the bottom of the hypertrophic zone and in mineralizing annulus fibrosus cells. E: In Col2a1-cKO growth plates, expanded regions of SPP1-negative hypertrophic chondrocytes are observed (red arrows) and only a few scattered hypertrophic chondrocytes are SPP1-positive (black arrows). IHC tissue sections were counterstained with hematoxylin. Scale bars  =  25 µm.