scholarly journals Intravascular neutrophils partially mediate the endometrial endothelial cell proliferative response to oestrogen in ovariectomised mice

Reproduction ◽  
2004 ◽  
Vol 127 (5) ◽  
pp. 613-620 ◽  
Author(s):  
B Heryanto ◽  
J E Girling ◽  
P A W Rogers

The aim of this study was to investigate the role of intravascular neutrophils in initiating endothelial cell proliferation following oestrogen treatment in ovariectomised mouse endometrium. Uterine tissues were collected from ovariectomised C57/CBA female mice 24 h after oestrogen treatment with or without systemic neutrophil depletion. Neutropenia was achieved with either an in-house anti-neutrophil serum (ANS) or Gr-1 monoclonal antibody. All mice received an i.p. injection of bromodeoxyuridine (BrdU) 4 h prior to dissection to allow visualisation of proliferating cells using immunocytochemistry. Endometrial sections were immunostained for BrdU, vascular endothelial growth factor (VEGF), and neutrophils (using ANS). Oestrogen treatment of ovariectomised mice significantly increased the number of intravascular neutrophils, whereas induction of neutropenia with either ANS or Gr-1 in conjunction with oestrogen treatment prevented this increase. Oestrogen treatment of ovariectomised mice also significantly increased the number of intravascular VEGF-positive cells; however, whereas induction of neutropenia with ANS significantly reduced this increase, Gr-1 did not. In both studies, neutropenia significantly reduced, but did not eliminate, the amount of endometrial endothelial cell proliferation. These results suggest a role for neutrophils in endometrial angiogenesis following acute oestrogen treatment; however, the presence of VEGF-positive cells even after induction of neutropenia suggests that more than one type of leukocyte may be involved.

Reproduction ◽  
2005 ◽  
Vol 129 (6) ◽  
pp. 765-777 ◽  
Author(s):  
Lisa M Walter ◽  
Peter A W Rogers ◽  
Jane E Girling

The role of progesterone (and oestrogen) in endometrial angiogenesis remains controversial. The aims of this study were to quantify endometrial angiogenesis in pregnant mice and to investigate the role of progesterone in promoting endothelial cell proliferation in ovariectomized mice. Uteri were collected on days 1 to 4 of pregnancy when circulating progesterone concentrations were increasing, prior to implantation. Before dissection, mice were injected with bromodeoxyuridine (BrdU) enabling proliferating endothelial cells to be quantified with CD31/BrdU double-immunohistochemistry. There was a significant increase in proliferating endothelial cells on day 3 of pregnancy when plasma progesterone also increased. To determine if this endothelial cell proliferation was due to progesterone, an experiment was performed on ovariectomised mice. One group was treated with a single oestradiol injection on day 8 after ovariectomy, followed by a no-treatment day and three consecutive daily injections of progesterone. Other groups were treated with either the vehicle, oestradiol or progesterone injections only; all were dissected on day 13 following ovariectomy. Unexpectedly, mice treated with progesterone-only had the highest amount of endothelial cell proliferation and oestrogen priming was found to significantly reduce this progesterone-induced endothelial cell proliferation. To determine if this proliferation is mediated by vascular endothelial growth factor (VEGF), a further experiment in which VEGF anti-serum was administered concurrently with the progesterone injections was performed. Endothelial cell proliferation was reduced but not abolished suggesting progesterone-induced endometrial angiogenesis is only partly mediated by VEGF. Results indicate that oestrogen priming is not required for progesterone to stimulate endometrial endothelial cell proliferation and that oestrogen inhibits progesterone-induced angiogenesis in ovariectomised mice.


Endocrinology ◽  
2008 ◽  
Vol 149 (12) ◽  
pp. 6076-6083 ◽  
Author(s):  
Graham W. Aberdeen ◽  
Stanley J. Wiegand ◽  
Thomas W. Bonagura ◽  
Gerald J. Pepe ◽  
Eugene D. Albrecht

To assess whether there is a link between estrogen, vascular endothelial growth factor (VEGF), and early aspects of uterine angiogenesis, an acute temporal study was conducted in which ovariectomized baboons were pretreated with VEGF Trap, which sequesters endogenous VEGF, and administered estradiol at time 0 h. Serum estradiol levels approximated 500 pg/ml 4–6 h after estradiol administration. VEGF mRNA levels in endometrial glandular epithelial and stromal cells were increased to values 6 h after estradiol that were 3.74 ± 0.99-fold (mean ± se) and 5.70 ± 1.60-fold greater (P < 0.05), respectively, than at 0 h. Microvessel interendothelial cell tight junctions, which control paracellular permeability, were present in the endometrium at time 0 h, but not evident 6 h after estradiol administration. Thus, microvessel paracellular cleft width increased (P < 0.01, ANOVA) from 5.03 ± 0.22 nm at 0 h to 7.27 ± 0.48 nm 6 h after estrogen. In contrast, tight junctions remained intact, and paracellular cleft widths were unaltered in estradiol/VEGF Trap and vehicle-treated animals. Endometrial microvessel endothelial cell mitosis, i.e. percent Ki67+/Ki67− immunolabeled endothelial cells, increased (P < 0.05) from 2.9 ± 0.3% at 0 h to 21.4 ± 7.0% 6 h after estrogen treatment but was unchanged in estradiol/VEGF Trap and vehicle-treated animals. In summary, the estrogen-induced disruption of endometrial microvessel endothelial tight junctions and increase in endothelial cell proliferation were prevented by VEGF Trap. Therefore, we propose that VEGF mediates the estrogen-induced increase in microvessel permeability and endothelial cell proliferation as early steps in angiogenesis in the primate endometrium.


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