MRTFA KO mice develop an osteopenic phenotype at an earlier age when challenged with a high fat diet (HFD). Representative 3D images of cortical region (mid-shaft of femurs) and trabecular region of femurs of MRTFA KO or WT male mice on LFD (10% fat) or HFD (60% fat) generated by μCT analysis are shown in A. Twenty five mice (WT LFD n = 6, KO LFD n = 8, WT HFD n = 5, KO HFD n = 6) at the age of 12 weeks were analyzed for this study. The cortical thickness (B), connectivity density (C), and trabecular volume/total volume ratio (D). Data are expressed as mean ± SEM. *p < 0.05.