Bone and Cartilage Staining for Skeletal Preparations

While phenotypes affecting the development of the craniofacial region, axial skeleton, and limbs can sometimes be inferred from observations alone, revealing the composition of the skeleton of Xenopus tadpoles and froglets can often add more detailed and useful information. An estimated 11% of recognized rare genetic diseases are classified as skeletal disorders, with the latest nosology linking 552 genes. Both commonly used species of Xenopus, as tetrapod vertebrates, are highly amenable to genetic manipulation and have been used to study skeletal development as well as craniofacial and skeletal disorders. The following protocol for post-fixation bone and cartilage staining can be robustly used to characterize skeletal phenotypes in detail, using standard Alizarin red (bone) and Alcian blue (cartilage) histological stains. The protocol takes several days to a week to complete, depending on the stage of the animal, but is not labor-intensive.