2.2.2. Polyfluorochrome Sequential Labeling of Bone

Bone formation was assessed by sequential labeling with Calcein and tetracycline (Sigma-Aldrich), which were deposited at the active site of mineralization. The fluorochromes were administered by intraperitoneal injection in the following sequence: calcein (20 mg/kg) was added to 2% NaHCO3 buffer and given to three 19-week-old mice randomly selected from each group (*n* = 9). Four days later, the same mice were injected with tetracycline (30 mg/kg) in 0.9% normal saline. The sections were observed by fluorescence microscopy.
