272. Progesterone stimulates endothelial cell proliferation, but not stromal cell proliferation, in mouse endometrium
L. M. Walter A , P. A. W. Rogers A and J. E. Girling ACentre for Women’s Health Research, Monash Institute of Medical Research, Clayton, VIC, Australia
Reproduction, Fertility and Development 17(9) 112-112 https://doi.org/10.1071/SRB05Abs272
Submitted: 26 July 2005 Accepted: 26 July 2005 Published: 5 September 2005
Abstract
Previous studies have suggested that progesterone stimulates stromal cell (SC) proliferation in the mouse endometrium1. However, these studies have not differentiated endothelial cells (EC) from other SC. In this study, we investigated the effects of progesterone on cellular proliferation in ovariectomised mouse endometrium. We hypothesised that progesterone would stimulate both SC and EC proliferation. One group of CBA × C57 mice (n = 6) were treated with a single injection of 100 ng of estradiol on day eight following ovariectomy, followed by a day with no treatment and three consecutive daily injections of 1 mg progesterone. Other groups were treated with either the vehicle (n = 5), estradiol (n = 4) or progesterone (n = 5) injections only. All groups were dissected on day 13 after ovariectomy, 4 h following a BrdU injection. CD31/BrdU double staining immunohistochemistry allowed proliferating EC to be differentiated from proliferating SC. Mice treated with progesterone only had significantly higher EC proliferation in comparison to females treated with progesterone following oestrogen priming (P = 0.05) or vehicle only (P = 0.01) (progesterone only: median = 97.3 proliferating EC (PEC)/mm2 [range = 60.8–203.4]; oestrogen plus progesterone: 41.0 PEC/mm2 [8.9–86.9]; vehicle only: 0.0 PEC/mm2 [0.0–3.1]). Unexpectedly, there was no significant difference in SC proliferation among the treatment groups (progesterone only: 50.1 PSC/mm2 [39.2–102.6]; oestrogen plus progesterone: 46.1 PSC/mm2 [12.6–120.8]; vehicle only: 44.8 PSC/mm2 [17.3–68.4]). To determine if VEGF had a role in the progesterone-induced EC proliferation, the previous experiment was repeated with the inclusion of mice treated with VEGF anti-serum. The addition of VEGF anti-serum significantly inhibited progesterone-induced EC proliferation (46.8 PEC/mm2 [38.9–128.0]; P = 0.04], but had no effect on SC proliferation (P = 0.3). These results demonstrate that progesterone stimulates endometrial EC proliferation, but not SC proliferation as reported by earlier studies1. Studies are currently underway to further investigate the role of VEGF in mediating progesterone effects on endometrial EC.
(1) Clarke, C.L. and Sutherland, R.L. (1990) Endocrine Reviews 11, 266–301.
