Increased Apoptosis Of CD4+CD25+Regulatory T Cells From Spleen Of Severe Aplastic Anemia Mouse Model

Objective To explore the mechanism of apoptosis in spleen regulatory T(Treg) cells from severe aplastic anemia(SAA) mouse model induced by interferon (IFN-y) in combination with busulphan(BU).Methods The BALB/c female mice SAA model was induced by intraperitoneal injection with IFN-γ and intragastric administration with BU(combined group, n=16), with BU group (n=16), IFN-y group (n-16) and normal group (n=16) as controls. Spleen Treg cells of each group was isolated by immunomagnetic beads isolation. The isolation purity and apoptosis rate of spleen Treg cells was detected by flow cytometry, and the change of expression of Akt and TGF-β in each group was obtained by western blot.Results Increase of apoptosis rate in spleen Treg cells was found in combined group ((33.21±0.65)%), having difference compared with other three groups (P<0.05). The results also showed an decrease of the expression of Akt and TGF-β in combined group (0.3±0.05and0.17±0.05), having difference compared with other three groups too (P<0.05).Conclusions Excessive apoptotic Treg cells was found in severe aplastic anemia mouse model, which may be one of the reasons for reduction of Treg cells in patients with aplastic anemia. The expression of Akt and TGF-β down-regulating is likely played a role in increased apoptosis of Treg cells.