[The Hematopoietic Protective Effect of PDGF-BB on Radiation-Induced Myelosuppression Model Mice].

ABSTRACT

OBJECTIVE: To investigate the hematopoietic protective effect of platelet-derived growth factor (PDGF)-BB on radiation-induced myelosuppression model mice and effect of anti-apoptosis of megakaryocyte line Meg-01 cells, and its possible mechanism. METHODS: Mice were radiated with 4 Gy of 137Csγ ray to establish the model of myelosuppression. Mice were weighed and peripheral blood cell were counted before radiation (day 0) and day 7, 14 and 21 after radiation. On the 21 st day, the mice were killed. The sternal tissues of the mice were taken for morphological observation, and the femoral bone marrow cells were cultured for the assay of colony cell forming units (CFU). Meg-01 cells were cultured without FBS for 24 h to induce apoptosis, and then treated with PDGF-BB for 48 h. The effects of PDGF-BB on the proliferation were investigated by cell counting. Flow cytometry was used to detect early apoptosis (Annexin V), mitochondrial membrane potential (JC-1) and the expression of caspase-3. RESULTS: Peripheral blood cell counts of mice showed that PDGF-BB stimulated the recovery of white blood cells, red blood cells and platelets after radiation (P<0.05), especially for white blood cells. Morphological examination showed bone marrow hyperplasia in PDGF-BB group, the numbers of megakaryocytes and their progenitor cells were higher than those in the control group. PDGF-BB significantly stimulated the formation of CFU-MK, CFU-GM, BFU-E and CFU-F. PDGF-BB showed a strong proliferation effect in the concentration range of 5-50 ng/ml (P<0.001). PDGF-BB (50 ng/ml) significantly reduced the positive expression of Annexin V (P<0.01). The mitochondrial membrane potential in the control group was decreased when compared with PDGF-BB group, which indicated that the number of apoptotic cells was increased (P<0.01). Besides, the expression of caspase-3 in PDGF-BB group was significantly lower than that in control group (P<0.05). CONCLUSION: PDGF-BB has a protective effect on the hematopoietic system of myelosuppression model mice, especially megakaryocytes and their progenitor cells. PDGF-BB has pro-proliferative and anti-apoptotic effects on Meg-01 cells, and the mechanism may be mediated through JC-1 and caspase-3 pathway.