FOXO1 and diabetes mellitus: However, under Dia conditions, the deletion of Foxo1 (OsxcretTAFoxo1f/f) significantly increased the proliferative activity of bone cells in comparison with controls (OsxcretTA) (P < 0.01, Fig. 1G), indicating deletion of Foxo1 in osteoblasts can restore the proliferation activity of bone cells inhibited by diabetes (Fig. 1G).