Figure 3
From: Flt1/VEGFR1 heterozygosity causes transient embryonic edema
Flt1 heterozygosity enhances embryonic edema in Aspp1−/− embryos.
(A–D) Lateral view of whole-mount embryos at E14.5 from crosses between Flt1+/−; Aspp1+/− and Aspp1−/− mice. Subcutaneous edema (arrowheads) is detected in all embryos except Aspp1+/− embryos. Flt1 heterozygosity greatly enhances edema in Aspp1−/− embryos. (E–H) Immunofluorescence confocal microscopy images of flat-mount embryonic back skin at E15.5 stained for PECAM-1 (red) and Flt4 (green). Partly-distended lymphatic vessels and lymphatic islands (arrowheads) are detected in mice carrying Aspp1−/− mutation. (I–L) Vascular permeability assay in E14.5 embryos. Frozen sagittal sections show the nuclei of surrounding tissues as well as BECs in mice carrying Flt1+/− but not Aspp1−/− mutation following intravenous injection of Hoechst 33258. (M) The edema index of Flt1+/−; Aspp1+/−, Aspp1−/− and Flt1+/−; Aspp1−/− embryos are significantly higher than Aspp1+/− embryos (Aspp1+/−, n = 6; Flt1+/−; Aspp1+/−, n = 4; Aspp1−/−, n = 8; Flt1+/−; Aspp1−/−, n = 3). (N) Vascular permeability is enhanced with mice carrying Flt1+/− mutation (n = 3 each group). (O,P) Western blot analysis using embryonic back skin at E14.5 shows that Src activity is elevated in Flt1+/−; Aspp1−/− mice but not in other littermates (n = 3 each group). Data are presented as mean ± standard error of the mean. ***P < 0.001, **P < 0.01 and *P < 0.05 as determined by one-way analysis of variance for inter-group comparisons and Tukey-Kramer method for group comparisons. N.S. = not significant.
