title: Immunohistochemical (Ki-67) study of endometrial maturation in mice after use of phosphodiesterase type 5 inhibitor.
abstract: BACKGROUND
  Uterine receptivity for the implantation is a complicated process, that ovarian factors (hormonal), endometrium and embryo simultaneously are involved in this phenomenon. A successful implantation needs appropriate development of the endometrium. Furthermore, embryo must be capable of reacting with the endometrium and producing suitable adhesion molecules. This study aimed to examine one of endometrial maturation indices in mice before implantation, i.e., proliferation of stromal cells.
  
  
  METHODS
  A total of 40 adult female mice were divided into four groups: Control, gonadotropin, gonadotropin + progesterone, and gonadotropin + sildenafil citrate. The three experimental groups were first injected 7.5 IU of human chorionic gonadotropin (HCG) and then 7.5 IU of human menopausal gonadotropin (HMG). Then, every two female mice were placed in a cage with a male mouse for mating. Two groups were injected 1 mg of progesterone and 3 mg/kg of sildenafil citrate at intervals of 24, 48, and 72 h after injection of HMG. After 96 h, all the mice were killed, and their uterine samples subjected to tissue passage and prepared for analysis. Immunohistochemical method, Ki-67, and stromal mitotic cell count were used in this study.
  
  
  RESULTS
  Our observations in all groups showed changes in the luminal epithelium. ANOVA analysis Ki-67-positive stromal cells among all groups were not statistically significant.
  
  
  CONCLUSIONS
  The results showed that administration of HMG and HCG following that of progesterone and sildenafil citrate could change the indices of endometrial maturation, and they were not involved in the phase immediately before implantation in stromal mitotic index.
authors.affiliation: Department of Anatomical Sciences and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Bahman
authors.initials: B
authors.lastname: Rashidi
authors.affiliation: Department of Anatomy and Histology, School of Medicine and Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Jafar Soleimani
authors.initials: JS
authors.lastname: Rad
authors.affiliation: Department of Anatomy and Histology, School of Medicine and Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Leila Roshangar
authors.initials: LR
authors.lastname: Rad
keywords: Endometrium; implantation; sildenafil citrate