Expression of VEGF-A, CD31, MMP-2, CGRP, Col I, Col II, and OPN mRNA over time (E12.5, E14.5, E17.5, E18.5, P0, P1 and P). The abundance of VEGF-A, CD31, MMP-2, CGRP, Col I, Col II, and OPN mRNA was normalized to GAPDH at E12.5, E14.5, E17.5, E18.5, P0, P1 and P5, followed by normalization to the target gene expression at E12.5. The white bars represent the mandible, and the blacks bar represent the tibia. a, VEGF-A mRNA expression; b, CD31 mRNA expression; c, MMP-2 mRNA expression; d, CGRP mRNA expression; e, Col I mRNA expression; f, Col II mRNA expression; g, LYVE-1 mRNA expression; h, OPN mRNA expression. Differences between E12.5, E14.5, E17.5, E18.5, P0, P1 and P5: 1; P<0.05, 2; P<0.01, 3; P< 0.001. *Compared with E12.5 and others; #compared with the mandible and the tibia. All error bars represent mean ± SD.