Figure 5

Transcription of osteonectin (A-D), col2a (E-I) and col10a (J-N) in parasagittal sections of phenotypical normal vertebrae from 15 g salmon reared at low intensive (l.i.) and high intensive (h.i.) temperature intensive regime. Numbered bars indicate zones of chondrocytes divided into the sub-groups: 1.resting, 2.proliferating and 3.hypertrophic chondrocytes. A. Osteonectin specific staining of two vertebrae from l.i. revealed staining in zone 1 and 2. B. Strong transcription of osteonectin is present in osteoblasts lining the growth zone at the endbone and in the hypertrophic chondrocytes (arrow) in l.i. C. The arch centra from h.i. Notice increased transcription of osteonectin; D. Transcription of osteonectin in osteoblasts from h.i. appears decreased compared to l.i. E. Col2a staining of 3 vertebrae from l.i. Col2a mRNA localized to chondrocytes in zone 1 and 2. F. Higher magnification show distinct staining of col2a in the chordoblasts. G. Higher magnification of the arch centra with col2a mRNA in zone 1 and 2. H. In the corresponding area of h.i. a similar, but weaker pattern of col2a transcription is visible in the chordoblasts. I. Increased temperature lead to a distorted morphology and a more homogenous but weaker staining of col2a. J. Staining of a large section from l.i. covering 2 vertebrae show that col10a mRNA localizes to zone 3 (arrows). K. and L. Higher magnification reveal col10a specific staining in hypertrophic chondrocytes (arrow) and along the rims of the vertebral body (arrowhead). Black bar indicates the narrow zone of transcription restricted to hypertrophic chondrocytes. M and N. Corresponding area from h.i. show a wider zone of col10a positive hypertrophic chondrocytes (black bar). Ventral side to the left. Scale bar A,E,J:200 μm, B-D,F-I,K-N,:100 μm.