Recombinant neuregulin-1 beta preserves neural stem cell proliferation through extracellular regulated protein kinases signaling pathway in oxygen and glucose deprivation environment / 中华地方病学杂志

ABSTRACT

Objective To investigate the influence of recombinant neuregulin-1 beta (rhNRG-1β) on neural stem cell proliferation through extracellular regulated protein kinases (ERK) signaling pathway in oxygen and glucose deprivation (OGD) environment.Methods Neural stem cells were obtained from embryonic brain of mice pregnant for 14-17 d,cultured and identified by immunochemical staining through detection of the indicator nestin using the SABC-FITC (POD)double standard kit.Neural stem cells were divided into three experiment groups (OGD group,control group and OGD + rhNRG-1β group).Control groupidentified neural stem cells,2 × 107,were cultured for 3 h in the 24-hole culture plate with DMEM/F12 complete culture medium;OGD groupneural stem cells,2 × 107,were cultured in the 24-hole culture plate deprived glucose DMEM/F12 in a wet airtight container (37 ℃ constant temperature),cells were cultured with mixed gas of nitrogen (950 ml/L) and oxygen (50 ml/L) for 1 h,and then the culture medium was replaced with complete culture medium and cultured for 3 h;OGD + rhNRG-1β groupbefore OGD intervention,100 μg/L rhNRG-1β was given for 3 h.Neurospheres formationthe three groups of stem cells were dispersed into single cells,1 × 106/ml cells were inoculated to culture plates containing cover slips coated with poly lysine,and cultivated for 7 d,and neurospheres formation of the 3 groups of neural stem cells was observed under microscope,which was aimed to record neural stem cells proliferation changes.Colony formationthe three groups of stem cells,vaccinated in 60 mm in a petri dish,2 × 107 in number,were cultivated in complete culture medium for 24 h.The colony formation of the three groups of cells was observed under microscope,and neural stem cells proliferation changes were observed.Western blottingthe change of phosphorylation ERK (pERK) protein of the three groups of stem cells was determined,and the effect of pERK protein expression regulated by rhNRG-1β in mice neural stem cells proliferation through ERK signaling pathway was observed.Results Microscopically the primary cultured stem cells grew in single or in pairs,in a round shape;neural stem cell proliferated in clumps or colony;neural stem cells expressed the specificity of nestin protein markers with fluorescent yellow-green color.The differences in the aspects of the average diameter of neurospheres and neurospheres quantity in the neural stem cells between groups were statistically significant (F =693.66,1 002.09,all P ＜ 0.01),and among them the neuropheres formation of OGD group was significantly suppressed.Formation quantity and average diameter in OGD group [(88.78 ± 7.14) numbers,(62.12 ± 2.52) μm] were significantly lower than those in the control group [(246.34 ± 8.67) numbers,(128.45 ± 2.33) μm] and those in OGD + rhNRG-1β group [(237.87 ± 6.61) numbers,(118.37 ± 2.71) μm,all P ＜ 0.01].The difference of colony formation rate of neural stem cell was statistically significant (F =132.03,P ＜ 0.01),and among them colony formation of OGD group significantly suppressed.Formation rate in OGD group [(11.65 ± 0.94)％] was significantly lower than that in the control group [(33.23 ± 2.93)％] and that in OGD + rhNRG-1β group [(31.42 ± 2.61)％,all P ＜ 0.01].Western blotting showed that the difference of pERK protein expression of neural stem cells between groups was statistically significant (F =63.76,P ＜ 0.01).Relative expression of the pERK protein in OGD group (0.487 ± 0.072) was significantly lower than that in the control group (1.013 ± 0.112) and that in OGD + rh-NRG-1β group (1.752 ± 0.278,all P ＜ 0.01).Conclusion rhNRG-1β preserves neural stem cell proliferation with phosphorylation ERK protein expression up-regulated in oxygen and glucose deprivation environment.