Objective: The present study aimed to investigate whether genistein, a potent phytoestrogen mainly found in soybean,
modulated the expression of TLRs 2, 3, 4 and 9 proteins in human endometrial epithelial cell line RL95-2 under basal and
polyinosinic-polycytidylic acid (poly I: C) stimulated conditions to mimic viral infection. The genistein effects were also compared with 17β-estradiol.
Material and Method: The RL95-2 cells were cultured in the estrogen-deprived media with or without poly I: C 30 min prior
to incubation with genistein (10-7, 10-6 or 10-5 M) or 17β-estradiol (10-9 M) for 48 h. The TLRs protein expression was
analyzed by semi-quantitative Western blot.
Results: The cells expressed TLRs 3, 4 and 9 but a very low level of TLR2 proteins. Poly I: C significantly increased the TLRs
2 and 9 protein expressions whereas the TLRs 3 and 4 were reduced. Under basal condition, genistein at 10-7 M increased the TLR2 while 17β-estradiol decreased the TLR4. All concentrations of genistein and 17β-estradiol attenuated the poly I: C induced increase in the TLR2. By contrast, both genistein at 10-5 M and 17β-estradiol further potentiated the TLR4 suppressed by poly I: C. Only 17β-estradiol was found to antagonize the poly I: C-induced changes in TLRs 3 and 9.
Conclusion: Taken together, the present results that genistein increased the basal TLR2 and attenuated the viral componentinduced TLR2 protein expression in human endometrial epithelial cells may indicate the potential role of this soy isoflavone in promoting the uterine immune function and probably alleviating the inflammation of endometrium following pathogen invasion.

Keywords: Phytoestrogen, Toll-like receptor, Endometrium, Estrogen, Poly I: C