Experimental study of proliferation and differentiation of peripheral blood stem cells into Schwann cells induced by low frequency electrical stimulation / 中华物理医学与康复杂志

ABSTRACT

Objective To investigate in vitro possible mechanisms by which low frequency electrical stimulation may stimulate peripheral blood stem cells' proliferation and differentiation into Schwann cells (SCs).Methods The original generation of peripheral blood stem cells was cultured using Sprague-Dawley (SD) rats.The third passage stem cells were divided into a low frequency stimulation group,an extracellular signal-regulated kinase (ERK) group,a combination group and a control group.All 4 groups were cultured in DMEM containing 2％ fetal bovine serum by adding the SC supernatant.The low frequency electrical stimulation group was given 1 h of continuous low frequency stimulation.For the ERK group 50 mmol/L of the inhibitor PD98059 was added.The combination group was given the inhibitor plus 1h of sustained low frequency electrical stimulation.The control group received no special intervention.Before and after induction the 3-(4,5-dimethyl-thiazol-2)-2,5-diphenyl tetrazolium bromide (MTT) assay was used to detect the absorbance value A of 4 cells at 570 nm (A750),and after induction Western blotting was used to determine cyclin D1 (cyclin D1) and cyclin-dependent kinases (CDK4).Results Before the intervention peripheral blood stem cells in each group had no significant differences in their A750 values.After the intervention,the A750 values of the low frequency electrical stimulation,the ERK group,the combination group and the control group were (1.051 ±0.058),(0.363 ±0.343),(0.894 ±0.343) and (0.758 ±0.047),respectively.This showed a statistically significant increase for all groups except the ERK group.The differences among the groups were also statistically significant.The expression of S-100,glial fibrillary acidic protein (GFAP) and P75 was highest in the low frequency electrical stimulation group,and in the ERK group they were the lowest.S-100,GFAP and P75 protein expression also was highest in the low frequency electrical stimulation group and lowest in the ERK group,and the inter-group differences were statistically significant.ERK expression showed no significant difference among the groups.Compared with the control group,the expression of phosphorylated extracellular signal-regulated kinase 1/2 (p-ERK1/2),cyclin D1 and CDK4 protein in the low frequency electrical stimulation group and the combination group were all significantly higher and the protein expression in the ERK group was significantly lower.The p-ERK1/2,cyclin D1 and CDK4 protein levels in the combination group were significantly lower than in the low frequency electrical stimulation group and higher than in the ERK group.Conclusions Low frequency electrical stimulation can promote peripheral blood stem cell proliferation and induce cell differentiation into Schwann cells,at least in vitro.The ERK signaling pathways are part of the signaling pathways of the proliferation and differentiation.