Species-specific Embryonic Jaw Bone Structure in Quail and Duck

Objectives: Proper bone mineralization and structure are important elements to establish good oral health. We can learn much about how bone mineralization and structure form by studying bone development in higher vertebrates. Our lab uses two avian known to have differences in bone mineralization in their lower jaws, quail and duck. The duck lower jaw has higher average mineralization than quail during development and adulthood. The objective of this study was to evaluate and measure species-specific differences in bone structure and shape.
Methods: Fertilized eggs of Japanese quail (Coturnix coturnix japonica) and white Pekin duck (Anas platyrhynchos) were incubated (37°C) until collected at embryonic stage HH39. To detect calcified bone (n=7/species), tissues were skinned, fixed (70% EtOH), stained (alizarin red), cleared (2,2-thiodiethanol) and imaged by multiphoton microscopy. To analyze bone histomorphology (n=6/species), tissues were fixed (Serra’s), paraffin embedded, stained (modified Goldner’s trichrome), and analyzed (OsteoMeasure).
Results: Alizarin red autofluoresces when bound to calcium and was used successfully to image the lower jaw by multiphoton microscopy. Analysis of the 3D renders showed differences in bone structure and shape between quail and duck. Species-specific differences were also seen in bone histomorphology. Quail lower jaw bones have significantly higher bone surface to bone volume ratio and a lower trabecular width than duck. Interestingly, no significant difference was found between duck and quail in bone volume to tissue volume ratio.
Conclusions: To the best of our knowledge this is the first time multiphoton imaging has been used to visualize intricate bone structure by whole mount alizarin red staining. In addition, species-specific differences can be seen in bone structure and shape, while still maintaining the same bone volume per tissue volume. Further studies will be needed to determine the precise mechanisms that control bone structure and mineralization. Supported by UMKC SOD Summer Scholars program.