Mesenchymal stem cells increase platelet counts in mice with immune-mediated thrombocytopenia and affect T-bet and GATA-3 gene expression

Objective To explore the effects of mesenchymal stem cells （ MSC ） treatment on platelet counts in mice with immune-mediated thrombocytopenia （ ITP） and the possible mechanism .Meth-ods ITP was induced by daily intraperitoneal injection of anti-platelet membrane CD 41 antibody （MWReg30） into BALB/c mice.The mice were then divided into experiment and control groups with 20 mice in each.Each mouse in experimental group was injected with 2×107 mesenchymal stem cells （MSC） through the tail vein .The numbers of blood platelets in mice from two groups were counted on days 5, 7 and 14 after MSC injection .Reverse transcriptase polymerase chain reaction （ RT-PCR） was performed to meas-ure T-bet and GATA-3 gene expression in peripheral blood mononuclear cells （ PBMCs ） at mRNA level on day 14.The levels of IFN-γ, IL-2, IL-4 and IL-10 in serum were detected by ELISA .Results The platelet counts in experimental group were significantly higher than those in control group on days 7 and 14 after MSC injection [（588.0±81.6）×109/L and （623.0±78.9） ×109/L vs.（317.0±90.1） ×109/L and （288.0± 87.8）×109/L ] （P〈0.05）.On day 14 after MSC injection, the T-bet expression at mRNA level in PBMCs from mice in experimental group was significantly lower than that in control group [（0.04±0.03） vs.（0.27 ±0.05）] （P〈0.05）, while the GATA-3 expression at mRNA level was higher than those in control group [ （0.14±0.04） vs.（0.07±0.05）] （P〈0.05）.Compared with control group, the concentrations of Th1 type cytokines such as IFN-γand IL-2 were remarkably down-regulated in experimental group [（3.1±1.7） pg/ml and （3.2±2.1） pg/ml vs.（10.3±4.8） pg/ml and （16.3±5.7） pg/ml]（P〈0.05）, while the con-centrations of Th2 type cytokines such as IL-4 and IL-10 were up-regulated in experimental group [（88.6± 15.2） pg/ml and （38.3±11.8） pg/ml vs.（32.7±5.7） pg/ml and （22.1±3.4） pg/ml ] （P〈0.05）. Conclusion MSC treatment can effectively increase platelet counts in mice with immune-mediated thrombo-cytopenia, which may be associated with the suppression of Th 1-dominant response mediated by abnormal ex-pression of T-bet and GATA-3. Key words: Mesenchymal stem cells;  Immune-mediated thrombocytopenia;  Mice;  Transcription factor T-bet ;  Transcription factor GATA-3