Fig. 4.

Daily injections of recombinant Osteolectin increased bone formation in mice. (A–E) Eight-week-old male wild-type mice were administered daily injections of PBS or recombinant Osteolectin (Oln) at 50 µg/kg/d (50), 100 µg/kg/d (100), 200 µg/kg/d (200), or 400 µg/kg/d (400) for 4 wk. Oln injections did not affect body mass (A), femur length (B), LS3 vertebra length (C), but 200 or 400 µg/kg/d significantly increased cortical bone volume/total volume and cortical thickness in the mid-femur diaphysis (D). Oln also significantly increased trabecular bone volume/total volume, connectivity density, number, and reduced trabecular spacing in the distal femur metaphysis (E) (Five mice per group in three independent experiments). (F and G) Wild-type mice were administered daily injections of PBS or recombinant Osteolectin (Oln) from 2 to 8 wk of age, then body mass, femur length, and LS3 vertebra length were measured at 8 wk of age (F), and Oln injection significantly increased trabecular bone volume/total volume and trabecular number and reducing trabecular spacing (G) (Six mice per sex per group in three independent experiments). (H and I) Percentages of Aggrecan⁺ growth plate chondrocytes that incorporated a 2-d pulse of EdU at 4 (H) or 8 (I) wk of age (Three mice per sex per age per group in three or four independent experiments per age). (J) Acan^CreER;Rosa26^{loxp-tdTomato/+} mice were administered daily injections of PBS or Oln from 2 to 8 wk of age, then the length of cortical bone that arose from chondrocytes since tamoxifen treatment was measured as in SI Appendix, Fig. S6A (Three mice per sex per group in three independent experiments). All statistical tests were two sided. All data represent mean ± SD. Statistical significance was assessed using one-way ANOVAs followed by Dunnett’s multiple comparison tests (A–E), Welch’s t test followed by Holm–Sidak’s multiple comparison test (femur length in F), Student’s t tests followed by Holm–Sidak’s multiple comparison tests (trabecular BV/TV and trabecular connectivity density in G–I), Mann–Whitney tests followed by Holm–Sidak’s multiple comparison tests (trabecular spacing in G), and two-way ANOVAs followed by Sidak’s multiple comparison tests (body mass and LS3 vertebra length in F, and other panels in G), or Student’s t tests (J).