Fig. 4: YLLs augmented bone formation in vivo in normal adult mice.

Four-month-old female and male mice were treated with PBS control, YLL3 or YLL8 at 10 μg/kg or hPTH(1–34) at 25 μg/kg, s.c., 5x/week for 21 days. All mice received Calcein (green) and Alizarin red (red) at −8 and −1 days before euthanization. a Trabecular bone volume and surface-based bone formation were measured in the distal femur metaphysis (DFM). Columns represented individual values in each group and the error bars represented standard deviations. N = 7 animals in PBS and PTH-treated groups, and n = 8 mice in YLL3 and YLL8-treated groups. *p < 0.001 between the treated groups versus PBS-treated group using one-way ANOVA followed by Dunnett’s multiple comparison post hoc test for the trabecular bone area/tissue area and bone formation rate; and p < 0.05 between the YLL8-treated group versus PBS-treated group for the male Mineral apposition rate using one-way ANOVA followed by Dunnett’s multiple comparison post hoc test in the males. b Representative images were taken from the DFM trabecular region in the female mice. Scale bar = 100 µm. c Representative images were taken from the DFM trabecular region in the male mice. Scale bar = 100 µm. d Cortical bone mass was measured at the mid-femurs by microCT; bone strength was obtained by three-point bending of the femurs. Columns represented individual values in each group and the error bars represented standard deviations. N = 6 animals/groups. *p < 0.001 between the treated groups versus PBS-treated group for the cortical bone volume in the males, maximum load in the females and work-to-failure in the males using one-way ANOVA followed by Dunnett’s multiple comparison post hoc test; and p < 0.05 between the YLL8-treated group versus PBS-treated group for the cortical bone volume in the males, maximum load in the females and work-to-failure for the maximum load in the males and work-to-failure in the females using one-way ANOVA followed by Dunnett’s multiple comparison post hoc test.