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.
题目: PDGF-BB对放射诱导骨髓抑制模型小鼠的造血保护作用研究.
目的: 探讨血小板衍生生长因子（PDGF）-BB对放射诱导骨髓抑制模型小鼠的骨髓保护作用和减少人巨核细胞系Meg-01细胞凋亡的影响及其可能的机制。.
方法: 用4 Gy的137Csγ射线辐照小鼠，建立小鼠骨髓抑制模型。在小鼠辐照前（d 0）和照射后d 7、14和21对小鼠进行体重称量和外周血细胞计数；取d 21处死后的小鼠胸骨组织进行形态学观察和股骨骨髓细胞进行集落细胞形成单位的培养。无血清培养Meg-01细胞24 h诱导细胞凋亡，PDGF-BB处理Meg-01细胞48 h后进行细胞计数，应用流式细胞术检测细胞的早期凋亡、线粒体膜电位（JC-1）和凋亡蛋白酶Caspase-3活性的表达。.
结果: 小鼠外周血计数结果表明，PDGF-BB可刺激放射后小鼠白细胞、红细胞和血小板的恢复（P<0.05），对白细胞尤为明显。PDGF-BB处理组小鼠可观察到骨髓增生，巨核细胞及其祖细胞数量均高于对照组。细胞集落形成的培养结果显示，PDGF-BB处理组可明显刺激CFU-MK、CFU-GM、BFU-E和CFU-F的形成。不同浓度PDGF-BB处理Meg-01细胞后，结果显示，PDGF-BB在5-50 ng/ml浓度范围内对细胞具有较强的促进增殖作用（P<0.001）。PDGF-BB（50 ng/ml）可明显降低Annexin V的阳性表达（P<0.01）；与PDGF-BB处理组相比，对照组细胞中线粒体膜电位下降，表明凋亡细胞数量明显增加（P<0.01）；PDGF-BB处理组的Caspase-3的表达明显低于对照组（P<0.05）。.
结论: PDGF-BB对放射诱导骨髓抑制模型小鼠的造血系统具有保护作用，尤其是巨核细胞及其祖细胞。对Meg-01有促增殖和抗凋亡作用，其抗凋亡作用可能是通过JC-1和Caspase-3通路介导的。.
Keywords: Meg-01 cell; apoptosis; hematopoietic protection; platelet-derived growth factor-BB.