Bone Characterization in a Novel Dicer-Deficient Mouse Model Specific to Osteocytes

Osteocytes are mechanoreceptor of bones and their differentiation and functions are regulated by microRNAs (miRNAs). Dicer, an RNase III, cleaves pre-miRNAs into functional miRNAs. This study evaluated calvaria and femur phenotypes of Dicer deficiency driven by Sclerostin promoter transgenic mice (Dicer/Sost) with the sex and age-matched Dicer floxxed and Sostcre control mice using microCT, histological staining, and 3D morphometric analyses. Appropriate statistical analyses were used at a significance level of 0.05. The results demonstrated the differences in macro and microanatomical bone phenotypes between Dicer/Sost mice and their controls such as decreased trabecular and cortical bone volume fraction, thickness, and mineral density, and an underdeveloped posterior frontal suture, with abnormal shapes and sizes of calvaria and femurs. These results suggest that mature microRNAs play critical roles in osteocytes during endochondral and intramembranous bone formation in vivo.