Fig. 4

BrdU immunostaining and detection of apoptosis in mandibular incisors at E15. a–j Analysis of proliferation using BrdU staining in mandibular incisors at E15. a Sagittal section of mandibular incisors (200× magnification) of WT mice. b Schematic diagram. VL: vestibular lamina, SR: stellate reticulum, DP: dental papilla, LaM: labial mesenchyme, LiM: lingual mesenchyme, LaC: labial cervical loop, LiC: lingual cervical loop. c–f Sagittal section of cervical loop (1000× magnification). (G-I) Sagittal section of dental papilla (1000× magnification). j Analysis of cell proliferation using BrdU staining in mandibular incisors of WT and Bmp7+/− (ICR) mice at E15. Percent labeling index in respective tissues of WT and Bmp7+/− E15 embryos are shown. Labeled cells were counted under 1000× magnification. We counted approximately 500 nuclei under a light microscope and determined the labeling index as: (BrdU+ cells / total nuclei) / 100. Data are the mean + standard deviation (SD). ns: not significant, *P < 0.01 by Mann–Whitney U test. k Analysis of cell proliferation using BrdU staining in mandibular incisors of Usag-1+/+, Usag-1+/− and Usag-1 −/− (C57BL/6) mice at E15. Percent labeling index of mandibular incisors of Usag-1+/+, Usag-1+/− and Usag-1−/− embryos at E15. Data are the mean ± SD. ns: not significant, *P < 0.05 by Steel Dwass test. l TUNEL staining in mandibular incisors of Bmp7+/− (ICR), Usag-1−/− (C57BL/6), Usag-1−/−Bmp7+/− (F₂), and Usag-1+/− (C57BL/6) mice at E15. Under 100× magnification, the developing bone and cartilage (white arrow) are shown. Under 200× magnification, Meckel’s cartilage (white arrowhead), epithelium near the oral cavity (green arrowheads), and the mesenchyme near the tooth germ (red arrowheads) are shown. All bars: 100 μm