Abstract: Lycium barbarum polysaccharide (LBP) has anti radiation damage effect. Animal models of radiation injury were established by exposing Kunming mice to the linear accelerator X ray once. The irradiated mice were given intra-peritoneal injection with NS, LBP 50 mg/kg, LBP 100 mg/kg and LBP 200 mg/kg for 14 days respectively. The counts of WBC, RBC, PLT in peripheral blood and BMNCs were recorded BMNCs cell cycle cell apoptotic ratio and BMNCs surface adhesion molecule CD49d and CD44 were detected to illuminate the molecular mechanism of LBP in sheltering radiation injured haematogenesis. Experimental results show that: After irradiation, the mice were observed drank and ate less than before, slow of movement, lethargy, messy hair and poor of glossiness, demonstrating the success of radiation damage model establishment; At the same time, NS group compared with the normal control group, Peripheral blood WBC, RBC, PLT and BMNCs count decreased significantly (p<0.05), the cell proliferation of BMNCs was significantly decreased (p<0.05), the proportion of cells in S phase significantly decreased (p< 0.05), G₀/G₁ phase cell percentage was significantly increased, the apoptotic rate of BMNCs cells increased significantly (p< 0.05), cell adhesion molecule CD49d and CD44 expression was significantly reduced (p< 0.05); At the same time, compared with the NS groups, the results of LBP groups showed that the numbers of peripheral blood cells and BMNCs significant increased (p<0.05), the cell proliferation of BMNCs was significantly increased (p< 0.05), the proportion of cells in S phase increased significantly (p<0.05), G₀/G₁ phase cell percentage was significantly decreased, the apoptotic rate was significantly lower (p< 0.05), adhesion molecule CD49d and CD44 expression was significantly higher (p< 0.05). In summary for BMNCs, LBP may enhance cell proliferation, accelerate cell cycle transition from G₀/G₁ phase to S phase, reduce apoptotic ratio and up-regulate the expression of cell surface adhesion molecules CD49d and CD44, and finally promote the recovery of hematopoietic function in mice after radiation injury.

Key words: lycium barbarum polysaccharide (LBP), radiation injury, bone marrow mononuclear (BMNC), cell cycle, apoptosis