The regulation of tolerogenic dendritic cells by a Chinese herb formula improves abortion prone in mice

Background Abortion prone (AP) is a common clinical event. The underlying mechanism remains unclear. Traditional Chinese formulas are known to be efficient in the management of abortion. The purpose of this study is to observe the effects of Anzitiaochongtang (AZT), a traditional formulation of Chinese medicine, on improving AP in mice by regulating immune tolerance. Methods An established abortion model (CBA/JxDBA/2) was employed. AZT was prepared and administered to mice in a manner consistent with clinical practice. Tolerogenic dendritic cells (tDC) and type 1 regulatory T cells (Tr1 cell) in mice were analyzed by immunological approaches to be used as representative immune tolerant parameters. Results An AP model was established with CBA/J x DBA/2 mice. The expression of IL-10 in tDC and Tr1 cell frequency in the mouse decidua tissues were lower in the AP group than that in the normal pregnancy (NP) group. Administration of AZT up regulated the expression of IL-10 in tDCs and Tr1 cell generation in the decidua tissues, and improved the pregnancy and tissue structure in AP mice. The main mechanism by which AZT improves pregnancy in AP mice is that AZT enhanced the expression of galectin-9 in the epithelial cells of decidua tissues. Galectin 9 activates TIM3 on DCs to promote the IL-10 expression. The DCs induced more Tr1 cells in the decidua tissues. Conclusions Dysfunctional tDCs were detected in the AP decidua tissues. Administration of AZT improved pregnancy in AP mice by regulating tDC function and generation of Tr1 cells in the maternal-fetal interface.