Influence of cAMP signaling on osteoclast number and cathepsin K activity.

<p>After 5 days of differentiation, osteoclasts were incubated in serum-free medium for another 24 hours and the collected supernatant was analyzed for cathepsin K enzyme activity. Remaining cells were fixed, stained for TRAP and cells containing ≥ 3 nuclei were counted as osteoclasts. The effect of adenylyl cyclase activator NKH 477 on osteoclast number <b>(A)</b> and osteoclast cathepsin K enzymatic activity <b>(B)</b> from CIA rats 40 days p.i. and control rats 40 days post NaCl treatment is shown as <b>percentage to respective unstimulated osteoclasts</b> (unstimulated (100%) = continuous line). N (control/CIA rats) = osteoclast number: 10^-6M (6/6), 10^-8M (5/5), cathepsin K activity: 10^-6M and 10^-8M (6/6). Cells for osteoclastogenesis were seeded in triplicate and each supernatant was analyzed in duplicate. Box plots represent the 10^th to 90^th percentile of data sets. *p<0,05. CIA: collagen-induced arthritis, NKH 477: adenylyl cyclase activator, p.i.: post-immunization, TRAP: tartrate-resistant acid phosphatase