Volume-referent bone turnover estimated from the interlabel area fraction after sequential labeling

Area of Science:

• Bone biology and histomorphometry
• Inner ear anatomy and physiology

Background:

• Bone remodeling in the otic capsule is characterized by low turnover and unique spatial distribution of remodeling units.
• Previous methods for quantifying bone turnover in this compact bone are limited.

Purpose of the Study:

• To present a novel method for estimating volume-referent bone turnover using sequential osteofluorochrome labeling.
• To validate this new method against a classical quantification technique in canine bone specimens.

Main Methods:

• Sequential labeling of bone with osteofluorochromes in canine humerus specimens.
• Measurement of the fractional area between labels to estimate bone turnover.
• Comparison of results with a classical method calculating formative osteonal area and period.

Main Results:

• The new sequential labeling method yielded a bone turnover estimate of 7.4% (SEM 2.1%) per year.
• The classical method provided a comparable estimate of 6.9% (SEM 2.1%) per year.
• Sufficient agreement between the two methods was observed.

Conclusions:

• The developed method for estimating bone turnover using sequential labeling is applicable and accurate.
• This technique is suitable for future measurements of absolute bone turnover in sequentially labeled perilabyrinthine bone.