Fig. 5.

Conditional miR-378a knockout and miR-378a over-expression modulate bone mass and marrow fat accumulation.

(A-K) AAV-F4/80-Cre-ZsGreen and AAV-NC-ZsGreen were injected into the bone cavity of miRNA-378a^flox/flox littermate to generate BMM conditional miRNA-378a knockout mice (miRNA-378a^BMMs△) and their controls. 2 months after injection, the mice are sacrificed. n = 6 per group. (A) Timeline diagram of BMM conditional miR-378a knockout mice generation. (B-G) Representative μCT images (B) and quantitative μCT analysis of trabecular (C-F) and cortical bone (G) from lean miR-378a^BMMs△ and miRNA-378a^BMMs+/+ mice. (H) Representative images of osteocalcin staining (H, top). Red arrows mark osteoblasts. Scale bar: 50 μm; representative images of H&E staining (H, bottom). Scale bar: 100 μm. (I-K) Quantification of number of osteoblasts (I) and number and area of adipocytes (J-K). (L-V) Adeno-associated-virus-miR-378a-EGFP (AAV-miR-378a-EGFP) and adeno-associated-virus-NC-GFP (AAV-NC-EGFP) were injected into the bone cavity in obese mice with the same age and gender. 2 months after injection, the mice are sacrificed. (L) Timeline diagram of miR-378a-overexpressing mice generation. (M) Representative μCT images of AAV-miR-378a-EGFP and AAV-NC-EGFP treated mice. n = 6 per group. (N-Q) Quantitative μCT analysis of trabecular bone. (R) Quantitative μCT analysis of cortical bone. (S) Representative images of osteocalcin staining (S, top). Red arrows mark osteoblasts. Scale bar: 50 μm; representative images of H&E staining (S, bottom). Scale bar: 100 μm. (T-V) Quantification of the number of osteoblasts (T) and number and area of adipocytes (U-V) in distal femora. Data is shown as mean ± SD. *P < 0.05, **P < 0.01, ****P < 0.0001, ns, no significant. (Non-parametric test is used in Fig. 5 I and Fig. 5 T, Welch's test is used in Fig. 5 V, student t-test is used in others).