Effect of granulocyte colony-stimulating factor on the proliferation of rat bone marrow mesenchymal stem cells

Objective To investigate the effect of granulocyte colony-stimulating factor (G-CSF) on the proliferation of rat bone marrow mesenchymal stem cells (BMSCs) and its role in the differentiation from BMSCs into neuron-like cells.Methods The BMSCs of 16 SPF SD rats were isolated in vitro, and the cells were identified. The rats were given G-CSF according to the different concentrations. They were divided into G0-3 groups. The G0 group did not contain G-CSF, which was set as negative controls. G1-3 groups contained G-CSF 5, 10 and 20 ng/mL respectively, which were vaccinated to 96-well flat-bottom plate (100 μL per well) at a density of 1×105/mL. The changes of absorbance values (A) on day 1, 3, 5 and 7 after adding G-CSF in each group were detected by MTT assay, and the effect of G-CSF on the proliferation of BMSCs was observed. Twenty-four hours after BMSCs were pre-induced by basic fibroblast growth factor (bFGF), they were further induced according to glial cell line-derived neurotrophic factor (GDNF) and were grouped according to different concentrations of G-CSF combination (B1-5). B1 did not contain GDNF and G-CSF, and the changes of cell morphology were observed under microscope. The expression of GFR-1, a neuronal marker, was detected by reverse transcription polymerase chain reaction (RT-PCR).Results On day 1, 3, 5 and 7 after G-CSF was given, the A values in the G0 group showed decreasing tendency (F=23.5083, P0.05), and the A values in G1-3 groups showed increasing tendency (F1= 202.5940, F2= 1301.8815,F3= 1222.0091, all P0.05). In comparison of the A values between the groups at the same time point, the G2 and G3 groups were higher than the G1 group (P0.05). There were no significant differences between the G2 and G3 groups (P0.05). B2-5 cells became round and polygonal gradually, and dendrites stretching out and all expressing GFR-α1, while B1 neither had the similar changes nor expressed GFR-α1. The gray level ratios among all the induced groups were compared at the same time point (on day 1, 3, 5 and 7 after the induction). There were significant differences among B2-5 (P0.05).Conclusions G-CSF may promote the proliferation of BMSCs in rats, and its suitable concentration is 10 ng/mL. The combination of GDNF and G-CSF with suitable concentration may be more effectively inducing BMSCs to differentiate into neuron-like cells than GDNF alone.