目的探讨b-FGF壳聚糖载体(Chitosan carrier)缓释对神经干细胞分化为神经元的作用。方法原代培养和鉴定神经干细胞,随机分为b-FGF壳聚糖缓释组,壳聚糖对照组和b-FGF对照组,Image-pro Plus 2.0图像分析软件测量细胞突起长度,免疫组织化学方法检测分化细胞中NSE阳性细胞比例,Western blot法检测分化细胞中βⅢ-tubulin的表达和Akt 磷酸化程度。结果 48h诱导后,诱导壳聚糖对照组、b-FGF对照组和b-FGF壳聚糖缓释组神经元的分化率分别为38.5%、42.6%和70.8%。b-FGF壳聚糖缓释组与壳聚糖对照组神经元分化率上升( P <0.05),b-FGF壳聚糖缓释组与b-FGF对照组相比神经元分化率显著提高( P <0.05);诱导48h后,b-FGF壳聚糖缓释组与壳聚糖对照组和b-FGF对照组相比,神经元突起长度均出现显著增长,差异有统计学意义( P <0.05);b-FGF壳聚糖缓释组与壳聚糖对照组和b-FGF对照组相比βⅢ-tubulin表达显著增加( P <0.05);诱导5、15和30min后,与b-FGF对照组相比,b-FGF壳聚糖缓释组Akt磷酸化水平显著升高,差异有统计学意义( P <0.05)。结论 b-FGF经壳聚糖载体缓释后诱导神经元突起形成,提高神经元分化率,Akt磷酸化激活的信号途径可能参与b-FGF壳聚糖载体诱导神经干细胞过程神经元分化速度的调节。
Epidemiological studies have shown that particulate matter 2.5(PM_(2.5)) not only increases the incidence of cardiopulmonary illnesses but also relates to the development of neurodegenerative diseases. Considering that PM_(2.5)is highly heterogeneous with regional disparity and seasonal variation, we investigated whether PM_(2.5)exposure induced neuronal apoptosis and synaptic injuries in a season-dependent manner. The results indicated that PM_(2.5)altered the expression of apoptosis-related proteins(mainly bax and bcl-2), activated caspase-3 and caused neuronal apoptosis. Additionally, PM_(2.5)decreased the levels of synaptic structural protein postsynaptic density(PSD-95) and synaptic functional protein N-methyl-D-aspartate(NMDA) receptor subunit(NR2B) expression. These effects occurred in a season-dependent manner, and PM_(2.5)collected from the winter showed the strongest changes. Furthermore, the effect was coupled with the inhibition of phosphorylated extracellular signal-regulated kinase 1/2(p-ERK1/2) and phosphorylated c AMP-response element binding protein(p-CREB). Based on the findings, we analyzed the correlations between the chemical composition of PM_(2.5)samples and the biological effects, and confirmed that winter PM_(2.5)played a major role in causing neuronal apoptosis and synaptic injuries among different season samples.