Aberrant bone structure in FVIIIKO and PAR1KO mice. (A) Bone connective tissue staining with sirius red for collagen synthesis is depicted. C57BL, FVIIIKO and PAR1KO are shown, respectively, at NB and 14 weeks of age. Arrows point to diminished amount of trabeculae in FVIIIKO and PAR1KO mice compared with C57BL control. NB, newborn. (B) Quantification of the structural parameters of the tibial metaphysis such as BMD, BV:TV, Tb.N, Tb.Th, and Tb.Sp. in C57BL (black), FVIIIKO (white), and PAR1KO (blue) are shown graphically. Graphs show mean value ± SD (#P < .001; *P < .05, n = 4/group). (C) Quantification of serum osteocalcin measured by ELISA. C57BL (black), FVIIIKO (white), and PAR1KO (green) are shown. Bars depict mean value ± SD (**P < .05, n = 10 per group).