Bone basics

How to measure bone activity?

BFR explained

Osteoblasts: Fluorescent microscopy of verterbrae to evaluate dynamic histomorphometry, in particular bone formation rate (BFR). Mice were injected with the fluorescent dyes, Calcein (in green), on day 0 and Alizarin Red (in red), 7 days later. The distance between the Calcein and Alizarin Red labelling provides a measure of bone formation rate and more specifically, osteoblast activity.

TRAP explained

Osteoclasts: Brightfield microscopy of vertebrae to evaluate osteoclast activity with Tartrate-Resistant Acid Phosphate (TRAP) assay Plastic sections of mouse L3-L4 vertebrae were used. The number of TRAP+ cells (in red) on bone surface provides a measure of osteoclast activity.