Introduction: Recently it has been reported that Astragalus membranaceus injection (AMI) inhibits immune responses, but whether it affects alloimmunity is not clear. It has been shown that the CD4(+) CD25(+) regulatory T cells (Treg) down-regulate immune responses. The aim of our study was to investigate the effects of AMI on allograft survival and its relation to Treg.
Materials and methods: Allografted mice were administered AMI for 14 consecutive days with observations of graft survival. The specific recall response, the ratio of Treg, the expression of Foxp3 mRNA, and interleukin (IL)-10 secretion were measured by mixed lymphocyte reactions (MLR), FCM, reverse transcriptase-polymerase chain reaction, and radioimmunoassay, respectively.
Results: AMI significantly prolonged allograft survival by up-regulating the Treg ratio and promoting Foxp3 expression (P < .05). The ratio of Tregs, the expression of Foxp3 mRNA, and the IL-10 level in the AMI administration group increased from day 7, to reach a maximum at day 14, recovering to the initial level on day 21. No obvious difference was detected between the AMI and a cyclosporine group.
Conclusion: AMI administered in vivo prolonged allograft survival associated with promotion of Treg activities.
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