Fig. 4.
Pregnancy enhances vomeronasal organ (VNO) neurogenesis. (a) Coronal VNO sections immunolabelled with Ki-67, proliferating cell nuclear antigen (PCNA), and endogenous doublecortin (Dcx)-DsRed in 19/20-day pregnant females and control females of same age. Dotted lines show the limits of the VNO sensory epithelium. Scale bars, 50 μm. (b) Quantification of the densities of Ki-67- and PCNA-labeled cells, and relative abundance of Dcx-DsRed+ cells vs. total cells labeled with the nuclear dye DAPI; 19/20-day pregnancy induced increase in immature neurons labeled with all markers. Ki-67, PCNA, Student’s t-test, *P <0.05; **P <0.01. Dcx-DsRed, ANOVA: F3,27 = 4.44; *P <0.05, **P <0.01. The increase of Dcx-DsRed cells is not induced by exposure to male bedding for 20 days (bedding vs. control, P = 0.873) and fades 3 days after delivery (post-delivery vs. control, P = 0.77). (c) Immunostaining of BrdU+ cells in the VNOs of control and GD20 pregnant mice injected with BrdU at GD0. Scale bars, 50 μm. (d) Quantification of BrdU+ cells in the VNOs of GD1 and GD20 pregnant mice and their non-pregnant controls injected with BrdU at GD0. The overall density of newborn cells marked with BrdU decreases at GD20, but not at GD1. Student’s t-test, **P <0.01. (e) VNO coronal sections labeled with Ki-67 antibody at different gestation days (GD). Scale bar, 20 μm. (f) Quantification of Ki-67+ nuclei density in the VNO at the different gestation days. Two-way ANOVA: F1,33 = 5.38; **P <0.01; n = 34