Fig. 3. Impaired embryo development and lack of angiogenesis in uteri of Cx43 conditional knockout mice on day 8 of gestation. (A) Hematoxylin and Eosin staining of uterine sections obtained from Cx43^fl/fl (a,b) and Cx43^d/d (c,d) mice on days 7 and 8 of pregnancy. Note that implanted embryos (E) develop poorly in Cx43^d/d mice compared with those in Cx43^fl/fl mice. Histological analysis by Hematoxylin and Eosin staining of perfused uterine sections obtained from pregnant Cx43^fl/fl (e) and Cx43^d/d (f) mice on day 8 of pregnancy. E, implanted embryo; M, the mesometrial region. Note the extensive vasculature in the uteri of Cx43^fl/fl mice and the lack of it in the uteri of Cx43^d/d mice. (B) Immunohistochemical staining (indicated by red deposits) for Pecam in pregnant uteri. Uterine sections of Cx43^fl/fl (a-c) and Cx43^d/d (d-f) mice on day 7 (a,b,d,e) and day 8 (c,f) of pregnancy are shown (n=3). (C) Uterine sections collected from mice on day 8 of pregnancy were subjected to immunoflouroscence employing anti-connexin 43 (a) and anti-Pecam1 (b) antibodies. c represents a merge of both Cx43 and Pecam staining indicating the expression of Cx43 in the stromal cells but not in the endothelial cells (n=2). (D) Uterine sections from Cx43^fl/fl (a) and Cx43^d/d (b) mice on day 8 of gestation were subjected to immunohistochemistry using an antibody against Ki67, a marker of cell proliferation (n=2).