EXPERIMENTAL-MODEL IN-VIVO FOR QUANTITATIVE ASSESSMENT OF BONE-RESORPTION INHIBITION

Quantitative assessment of bone resorption inhibition in vivo is not e asily accomplished; methods relying on a count of osteoclasts are ques tionable, and histomorphometric evaluation of the bone mass presents s everal technical problems as well. The authors developed a simple meth od to measure the inhibition of bone resorption by study of the proxim al tibial metaphysis of growing rats: the height of the perichondrial bone ring was taken as an index of the balance between osteoblastic an d osteoclastic activity because any agent that inhibits osteoclasts (w ithout interference with osteobtasts) produces an increase in the heig ht of this anatomical structure. Since the ring is well demarcated by surrounding tissues, its height can be measured with accuracy and used for quantitative assessment of bone resorption inhibition. This model was tested with salmon calcitonin, and it provides evidence in vivo t hat this hormone inhibits osteoclastic bone resorption.