Ablation of Stat3 in osteoclasts resulted in decreased bone resorption without influencing bone formation.
A, osteogenic activity in the femora of 8-week-old WT and Stat3Ctsk mice represented by calcein and alizarin red double-staining. Seven-week-old mice received an intraperitoneal injection of 20 mg/kg calcein on day 0 and 40 mg/kg alizarin red on day 4 and then were sacrificed on day 7. The top panel shows a representative image of cortical bone, and the bottom panel shows a representative image of trabecular bone. B and C, MAR evaluated by histomorphometric analysis. Five pairs of male and female Stat3Ctsk mice and their Stat3fl/fl littermates were included. Error bars represent mean ± S.D.; *, p < 0.05. D, TRAP staining of femora from 8- and 20-week-old WT and Stat3Ctsk mice. Black triangles indicate TRAP+-multinucleated osteoclasts. E and F, number of TRAP+ multinucleated osteoclasts was counted. Five pairs of male and female Stat3Ctsk mice and their Stat3fl/fl littermates were included. Error bars represent mean ± S.D.; *, p < 0.05.