polysaccharides promote the proliferation of bone marrow haematopoietic progenitor cells and stromal cells in mice with aplastic anaemia.

Context: The effects of L. (Crassulaceae) polysaccharides (RRPs) on haematopoiesis are poorly understood.

Objective: To determine the effects of RRPs on haematopoiesis in mice with aplastic anaemia.

Materials And Methods: Aplastic anaemia was induced in Kunming mice by Coγ (2.0 Gy) irradiation and cyclophosphamide administration (50 mg/kg/day for 3 consecutive days; intraperitoneal injection). The effects of RRPs (10, 20, and 40 mg/kg; intraperitoneal injection) on haematopoiesis were analyzed using peripheral blood tests, histopathological examination of haematopoietic tissues, culture of haematopoietic progenitors and bone marrow stromal cells (BMSCs), and Western blotting of Fas and Fas ligand (FasL). The effects of RRPs on bone-marrow haematopoietic progenitors and BMSCs were also evaluated.

Results: Compared to anaemic controls, high-dose RRPs (40 mg/kg) significantly increased red blood cells (8.21 ± 0.57835 versus 6.13 ± 1.34623 × 10/L), white blood cells (5.11 ± 1.6141 versus l.54 ± 1.1539 × 10/L), and BMSCs (10.33 ± 1.5542 versus 5.87 ± 3.1567 × 10/L) in mice with aplastic anaemia (all  < 0.01). High-dose RRPs significantly increased the formation of colony-forming unit-granulocyte macrophage (CFU-GM), burst-forming unit-erythroid (BFU-E), and colony-forming unit-erythroid (CFU-E;  < 0.01). Fas and FasL protein expression in BMSCs decreased after RRPs administration. Especially at the high dose, RRPs (150 μg/mL) significantly promoted CFUs-E, BFUs-E, and CFUs-GM formation. RRPs (150-300 μg/mL) also promoted BMSC proliferation.

Discussion And Conclusions: RRPs helped to promote haematopoietic recovery in mice with aplastic anaemia, facilitating haematopoietic tissue recovery. This study indicated some mechanisms of the haematopoietic regulatory effects of RRPs. Our findings provide a laboratory basis for clinical research on RRPs.