Background: Uterine receptivity and implantation are complex processes requiring coordinated expression of molecules by zygote and uterus. Our objective was to evaluate the role of the endometrial expression of leukemia inhibitory factor (LIF) and its glycoprotein 130 (gp130) receptor molecules and their secretion in uterine flushing during the window of implantation in cases of primary unexplained infertility
Case presentation: The study was conducted on 25 infertile women with unexplained infertility for at least two years and 10 normal fertile women as a control group . Endometrial tissue and uterine flushing were obtained. Each tissue specimen was divided into two pieces; one piece was used for histological dating of the endometrium and for immunostaining of progesterone receptors, and the second was used for RNA extraction and PCR assay of LIF and gp130 mRNA expression. Serum estrogen and progesterone were measured for all subjects. LIF mRNA was expressed in the endometrium of all normal fertile women but significantly decreased in infertile women. LIF was not detectable in 88% of infertile women while it was fairly detectable in 12% of them. Gp130 mRNA was hardly detectable in both fertile and infertile women with no difference between them. Infertile women secreted significantly less LIF and gp130 molecules in the uterine flushing compared with normal fertile women.
Conclusions: Expression of LIF mRNA in endometrium could be used as a molecular marker of unexplained infertility. Assessment of secreted LIF and gp130 molecules in uterine flushing could be another useful and safe method for predicting successful implantation as well as for diagnosing and eventually treating women with impaired fertility using recombinant human LIF.