Introduction
Bony fish (i.e. teleosts) are emerging small-sized animal models to investigate bone
quality, metabolism, and disease pathomechanisms. In particular, species as the
swordfish (Xiphias gladius) [1] and killifish
(Nothobranchius furzeri) [2] have been recently
introduced to the musculoskeletal disciplines because of their peculiar hard tissue
biology. We carried out a comprehensive ex vivo analysis of bone tissue to compare
the hard tissue properties of the swordfish rostrum, and the killifish vertebral
bone with human bone tissue. This macromolecular study of the tissue composition
reveals species-dependent similarities and differences in tissue composition.
Material & Methods
Bone matrix composition of killifish (n=3), swordfish rostrum (n=3)
and humans (n=6) were analyzed using Raman spectroscopy. Spectra were
collected with the scan range from 400 to 1800 cm-1 . Twenty bone
spectra/sample were baseline-subtracted and averaged. Mineral-to-matrix
ratios (MMR) were calculated: v1PO4 (930–980 cm-1)/amide I
(1620–1700 cm1), v1PO4/amide III (1215–1300 cm-1) and
carbonate-to-phosphate ratio (CPR) CO3(1050–1100 cm-1)/v1PO4 [3].
Results
Both MMRs did not differ between swordfish and human samples (p>0.05 for
both) but were significantly different between killifish and the other two groups
(pswordfish0.05 for both).
Conclusion
Differences in mineral composition in the studied species
were evident. Low CPR in both fish was found in comparison to human bone. The low
CPR may be linked to differences in mineral metabolism required in the aquatic
environments. Generally, our results point towards the presence of the same
macromolecular components including phosphate, carbonate, amide I, and amide III in
all bone types. Further studies will help to better understand the width of hard
tissue properties contributing to individual bone quality characteristics across
species.
