Abstract: Objective: To investigate the effect of human early decidual stromal cells (DSCs) on the regulatory T cell (Treg cell) subsets in peripheral blood lymphocytes (PBLCs) of women with reproductive age. Methods：Treg cells of peripheral blood were isolated and cultured. DSCs were isolated and cultured from the decidual tissue of normal early pregnancy. When DSCs were passaged to the third or fourth generation, DSCs were randomly divided into 4 groups. ①Control group: PBLC cultured only, ②Co-culture group: PBLC+DSCs cultured together, ③LPS stimulation group: PBLC+DSCs Co-culture and LPS stimulation, ④PDTC blockade group: LPS stimulation group plus PDTC blocking. The IκBα protein was detected by Western blotting. The FoxP3 mRNA was detected by RT-PCR. The Treg cell subsets were detected by flow cytometry. Results：The purity of DSCs was more than 95%. The levels of IκBα protein and FoxP3 mRNA in the Co-culture group were significantly higher than those in the other three groups (P＜0.05). The levels of IκBα protein and FoxP3 mRNA in the LPS stimulation group were significantly decreased when compared with the Co-culture group, while two parameters in the PDTC block group were significantly increased when compared with the LPS stimulation group although be still less than those in the Co-culture group (P＜0.05). Flow cytometry showed that the percentage of Treg cell subset in the Co-culture group was significantly higher than that in the other three groups (P＜0.05). Compared to the Co-culture group, this value in the LPS stimulate group was significantly decreased. Interestingly, this parameter in the PDTC blocked group was significantly increased than that in the LPS stimulate group, although be still less than that in the Co-culture group (P＜0.05). Conclusions：Human early DSCs can increase the proportion of Treg cell subsets in the peripheral blood lymphocytes from childbearing age women. The potential mechanism of the decreased proportion of Treg cell subsets induced by LPS is related to the activation of IκB kinase and the degradation IκBα, then the activation of the NF-κB signaling pathway and thus inhibition of FoxP3 expression.

Key words: Decidua, Cells, cultured, Reverse transcriptase polymerase chain reaction, T-lymphocytes, regulatory, Immune tolerance, Lipopolysaccharides, Infection