Fig. 3

RANKL blockade retards ISO-induced osteopenia through inhibiting osteoclastic miR-21. a TRAP staining of osteoclasts (Oc) formed in direct co-culture with osteoblasts (Ob). Bars: 100 μm. *P < 0.05 compared to the WT-Ob without ISO group; ^#P < 0.05 compared to the WT-Ob with ISO group. b MiR-21 expression levels in isolated osteoclasts (Oc) and osteoblasts (Ob). c, d Micro-CT analysis of femoral bone mass and trabecular parameters. Bars: 500 μm. e, f TRAP staining for osteoclasts (black arrows indicated) and the quantification. White dashed lines indicate borders of the trabecular bone. Bars: 12.5 μm. g, h Calcein labeling of mineralized femoral surface and quantification of bone formation rates. Bars: 50 μm. i, j Toluidine blue staining showing osteoblasts (black arrows indicated) and the quantification. Bars: 12.5 μm. k ELISA analysis of serum bone remodeling markers. n = 4 per group (a), n = 3 per group (b) and n = 5 per group (c–k). RANK-Fc injected with or without osteoclast-targeted delivery of agomir-21 (Oc-agomir-21) was performed under the ISO challenge. Mean ± SD. *P < 0.05; NS not significant