体外氧糖剥夺损伤诱导信号转导和转录激活因子-3信号通路在海马神经元中的动态变化

Dynamic signal pathway changes of signal transducer and activator of transcription factor-3 inhippocampal neurons induced by oxygen and glucose deprivation in vitro

目的观察体外培养的大鼠海马神经元经氧糖剥夺损伤后信号转导和转录激活因子一3（signaltransducerandactivatoroftranscriptionfactor-3，STAT3）磷酸化及其核转移，探讨体外模拟的脑缺氧、缺血损伤细胞模型中STAT3信号通路的动态变化。方法选择新生24h内sD大鼠，取双侧海马神经元，用DMEM／F12培养基培养9d，氧糖剥夺处理4h，建立海马神经元氧糖剥夺损伤模型。运用免疫荧光技术，在激光共聚焦扫描显微镜下观察磷酸化STAT3（P—STAT3）的表达部位。采用Westernbloting技术检测海马神经元氧糖剥夺后不同时相点P—STAT3表达强度的变化。结果对照组P—STAT3在胞核表达不明显；而模型组在建模后1hP—STAT3在胞核内即有表达，3h达到高峰，各时相点与对照组比较，差异有统计学意义（P〈0．05）。结论氧糖剥夺损伤诱导海马神经元胞核中P—STAT3水平明显升高，提示海马神经元氧糖剥夺损伤后STAT3信号转导通路被过度激活。

Objective To observe the phosphorylation level and nuclear translocation of signal transducer and activator of transcription factor-3 （ STAT3 ） in hippocampal neurons induced by oxygen and glucose deprivation in vitro and discuss the dynamic changes of STAT3 signal pathway in an in vitro cell model of brain hypoxia and ischemia. Methods Hippocampal neurons from newly born SD rats （within 24 hours from birth） were cultured with DMEM/F12 for nine days, and then were transferred to oxygen and glucose deprivation environment for four hours to establish experimental cell models. The distribution of phosphorylated STAT3 （p-STAT3） in the hippocampal neurons in different groups was observed under laser scanning confocal microscope after immunofluorescence staining. Expression intensity of p-STAT3 at different time points after oxygen and glucose deprivation in the hippocampal neurons was detected by Western blotting. Results Expression of p-STAT3 was unobvious in the nucleus of the control group, but it was observed in the nucleus of the model group one hour after modeling, and peaked at three hour. Expression levels of p-STAT3 in the hippocampal neurons at each time point between the two groups showed significant difference （P 〈 0.05 ）. Conclusion Oxygen and glucose deprivation induces noticeable up-regulation of p-STAT3 in the hippocampal neuronal nucleus, which indicates tile over- activation of signal transduction pathwav of STAT3.