title: Sildenafil Effect on Nitric Oxide Secretion by Normal Human Endometrial Epithelial Cells Cultured In vitro.
abstract: BACKGROUND
  Sildenafil is a selective inhibitor of cyclic-guanosine monphosphat-specific phosphodiesterase type 5. It increases intracellular nitric oxide (NO) production in some cells. There are reports on its positive effect on uterine circulation, endometrial thickness, and infertility improvement. Endometrial epithelial cells (EEC) play an important role in embryo attachment and implantation. The present work investigates the effect of sildenafil on human EEC and their NO secretion in vitro.
  
  
  METHODS
  In this experimental in vitro study, endometrial biopsies (n=10) were washed in a phosphate buffered solution (PBS) and digested with collagenase I (2 mg/ml in DMEM/ F12 medium) at 37°C for 90 minutes. Epithelial glands were collected by sequential filtration through nylon meshes (70 and 40 μm pores), respectively. Epithelial glands were then treated with trypsin to obtain individual cells. The cells were counted and divided into four groups: control and 1, 10, and 20 μM sildenafil concentrations. Cells were cultured for 15 days at 37ºC and 5% CO2; the media were changed every 3 days, and their supernatants were collected for the NO assay. NO was measured by standard Greiss methods. Data were analyzed by one way ANOVA.
  
  
  RESULTS
  There was no significant difference between groups in cell count and NO secretion, but the level of NO increased slightly in the experimental groups. The 10 μM dose showed the highest cell count. EEC morphology changed into long spindle cells in the case groups.
  
  
  CONCLUSIONS
  Sildenafil (1, 10, and 20 μM) showed a mild proliferative effect on human EEC numbers, but no significant change was seen in NO production.
authors.affiliation: Fertility and Infertility Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran.
authors.forename: Mozafar
authors.initials: M
authors.lastname: Khazaei
authors.affiliation: Fertility and Infertility Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran.
authors.forename: Shiva
authors.initials: S
authors.lastname: Roshankhah
authors.affiliation: Fertility and Infertility Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran.
authors.forename: Rostam
authors.initials: R
authors.lastname: Ghorbani
authors.affiliation: Fertility and Infertility Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran.
authors.forename: Farzaneh
authors.initials: F
authors.lastname: Chobsaz
keywords: Endometrium; Epithelial Cells; Nitric Oxide; Sildenafil
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