Results for individual stains (e.g., DAPI, SOST, col1, col2) are shown in S4 Fig. Dashed, vertical white lines mark the border between vertebrae. (h) Double fluorescent ISH in the IVR, showing Col1a1 expression (red) in osteoblasts (black arrowhead) in the external region of the IVR and Col2a1 expression (green) in SOST-positive chordoblasts (gray arrowhead) in the internal region of the IVR (scale bar same as in e).
(f–g) ISH showing SOST expression in chordoblasts (gray arrowheads), identified by their distinct morphology and location. The blue and yellow squares mark the 2 regions of the intravertebral region shown in (f) and (g), respectively. (e–h) The IVR in the caudal vertebral column of medaka, (e) HE-stained section. (d) Double fluorescent ISH, showing both Col1a1 (red) and Col2a1 (green) expression in the SOST-positive osteoblasts (black arrowheads) of the NS and fin R and Col2a1 in the SOST-positive chondrocytes (white arrowhead) in the cartilaginous core of the fin R. (b–c) ISH showing SOST expression in the cartilaginous core of the dorsal fin R (white arrowheads) and surface osteoblasts of the fin R and NS (black arrowheads). The blue and yellow squares mark 2 regions in the dorsal fin R, shown in (b) and (c), respectively. (a–d) An NS of medaka vertebra and adjacent fin R. SOST expression in medaka vertebra and dorsal fin R. F Comp., compression force FEA, finite element analysis F Musc, muscle force F Tens., tension force VB, vertebral bone.
Strain magnitudes (no units) for all images are shown in the color bar on the right. Peak strains occur primarily near the external surfaces of the VB. (d) Strain distribution in the 3 numbered 2D transverse sections shown in (c). Locations of several transverse sections are marked by white dashed lines and are shown in (d). (c) Strain distribution in 2 contralateral views of a loaded vertebra. (b) 3D representation of von Mises strains in the vertebra. F Muscs acting on fish vertebrae are rather difficult to model because of the high complexity of the musculature as shown in S1 Fig and are represented here in a simplified manner. Lateral bending of the vertebral column during oscillatory swimming creates forces on the flat articular surfaces of adjacent centra, F Comp. (a) A simplified loading graphic of the forces applied to the model. FE, finite element FEA, finite element analysis HS, hemal spine NS, neural spine.įEA of strain distribution in a loaded medaka vertebra. The distal HSs are cropped in fluorochrome and FE renderings. Note similarity of peak strains predicted by FEA in (c) and regions of intense bone formation in response to load, indicated by fluorochrome double labeling (b). (c) FE model (left) and FEA results (right), showing von Mises strains in a loaded medaka vertebra. Alizarin red was injected at t = 0 weeks, and calcein green was injected at t = 6 weeks of swim training. (a–b) Bone formation detected by sequential intraperitoneal fluorochrome injections in untrained (a) and swim-trained (b) zebrafish (left, osteocytic) and medaka (right, anosteocytic), each of the 4 groups comprising n = 4 fish. Vertebral bone formation in response to load. HS, hemal spine NS, neural spine O, osteocytic lacunae. The vertebrae of both species are hourglass shaped along the cranio–caudal axis (see 3D representation in Fig 3A), with NS and HS extending caudally from the vertebral body. Inset images show unsegmented tomography slices at a higher magnification.
Note that the distal parts of the NS and HS were cropped in the original scans and are only drawn here for reference therefore, these parts do not contain lacunae in the zebrafish rendering. O, colored in black in the zebrafish scan, show the ubiquity of cells residing in the bone material of zebrafish while being completely absent from medaka bone material. High-resolution tomography of caudal vertebrae of zebrafish (left) and medaka (right). Anosteocytic vertebra of medaka and osteocytic vertebra of zebrafish.
0 kommentar(er)
