A quick whole-mount staining protocol for bone deposition and resorption

Osteoblasts and osteoclasts, two cell types important in bone development, are associated with enzymes capable of hydrolyzing phosphate groups. These enzymes are important for their function of bone deposition and resorption. Alkaline phosphatase (AP) activity is associated with the cell surface of osteoblasts, while osteoclasts secrete tartrate-resistant acid phosphatase (TRAP). Due to their shared enzymatic properties, we were able to develop a simple whole-mount staining protocol to stain for both enzymes (TRAP and AP) within the same teleostean tissue sample. In addition, we were able to perform each reaction individually. Further, AP and TRAP stains were maintained through decalcification, embedding, and sectioning procedures. Staining can also be conducted after sectioning depending on the question under investigation. These rapid staining protocols can thus be used to observe the processes involved in bone remodeling in whole teleost specimens, and/or the location of the stain can be determined through sectioning. The ability to observe bone deposition and resorption in such a capacity will significantly advance our understanding of bone remodeling throughout the life history of organisms and also within particular skeletal elements.