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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.
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BACKGROUND: Peripheral blood stem cells (PBSCs) can be enhanced and differentiates into all kinds of neural cells and produce several kinds of neural growth factors in vitro, and have been used to treat several kinds of neural diseases and they showed satisfactory outcomes. It is now a research focus to optimize the culture conditions to induce the stem cell to differentiate into neural cells. On the other hand, it also becomes a focus of its amplification and differentiation. OBJECTIVE: To make a review on researches on treating brain lesion, genetic defection or degenerating diseases using PBSCs during recent years.METHODS: Researching Pubmed database(1999-01/2009-09), using "peripheral blood stem cell, neural, repair" as research words and these Chinese words in CNKI database(1999-01/2009-09). RESULTS AND CONCLUSION: 221 articles were collected altogether including 41 Chinese articles and 180 English articles. Totally 27 articles were adapted altogether after rejecting published early, repeat and similar articles. PBSCs can be enhanced and differentiates into all kinds of neural cells in vitro, and delivered into central neural system and improve the function of lesion neural area. It is not fully understood the differentiation mechanism of peripheral blood stem cells, but numerous studies have shown that surface marker antigen of peripheral blood stem cells is closely associated with its biological characteristics. There are many studies addressing surface marker of peripheral blood stem cells, but researchers cannot identify a reliable marker that can directly label peripheral blood stem cells. Function of CD34 remains unclear, so the principle of CD34 as a marker of hematopoietic stem cells receives challenge. It is necessary to do further researches on issues on how to enhance survival rate of PBSCs in vivo and the tendency to differentiate into neural cells.
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Serum specific IgG (SIgG) antibodies of 32 patients with epidemic hemorrhagic fever (EHF) were sequentially determined by indirect immunofluorecent antibody test and their relationship to the types of the disease were analyzed in the present paper. The SIgG antibodies appeared practically on day 3 after the onset of the disease. Thereafter,the positive rates and the SIgG titres increased with the prolongation of the illness days and reached 100% positive rates and stable high titres till day 11 to day 12 after the onset of the disease. Furthermore, different types of the disease had.different SIgG response curves ,and there was a significant difference between the SIgG titres of different illness types statistically from day 7 to day 8 after the onset of the disease. These results suggest that the SIgG might be responsible for the immunopathogenesis of EHF.