Mechanisms by which Astragalus membranaceus injection regulates hematopoiesis in myelosuppressed mice.

The aim of this study was to investigate the mechanism underlying the effects of Astragalus membranaceus injection (AMI) on myelopoiesis in myelosuppressed mice. At 72 h after cyclophosphamide injection (250 mg/kg), the mice were administered AMI (500 mg/kg) intraperitoneally for 6 consecutive days or an equivalent volume of saline as a control. Murine colony-forming unit-fibroblast (CFU-F) formation, production of IL-6 and GM-CSF by bone marrow stromal cells (BMSC), and bcl-2 protein and mRNA expression in BMSC were measured by CFU-F assay, ELISA, immunohistochemistry and in situ hybridization. The results indicated that AMI improved the hematopoietic microenvironment by enhancing the BMSC survival and proliferation of CFU-F, production of IL-6 as well as GM-CSF by BMSC and bcl-2 protein and mRNA expression in BMSC, which promoted myelopoiesis. The data may provide a mechanistic basis for applying this ancient Chinese herb to promote hematopoiesis as an efficacious adjuvant therapy against myelosuppression induced by anti-cancer therapy. Copyright 2007 John Wiley & Sons, Ltd.