铅对海马神经细胞Brn-3a表达的影响与致凋亡作用

Effects of lead on the Brn-3a expression and the apoptosis in hippocampus neurons

目的 探讨体外条件下铅对神经细胞内转录因子Brn 3a的表达和致凋亡作用。方法 采用海马神经细胞体外培养建立细胞模型 ,醋酸铅的染毒浓度分别为 0 1、1、10、10 0、10 0 0 μmol L ,对照组给予等量培养液。染毒后 2 4h及 4 8h时MTT法测定各组细胞的存活率 ;免疫组织化学法测定Brn 3a的表达以及TUNEL法检测神经细胞凋亡。结果 引起海马神经细胞存活率明显下降的醋酸铅的最低浓度是 10 μmol L ,醋酸铅浓度越高 ,细胞存活率越低。1μmol L醋酸铅可引起Brn 3a阳性细胞积分光密度显著下降 (P <0 0 5 ) ,10 μmol L醋酸铅可引起Brn 3a阳性面积比的显著下降 (P <0 0 1)。 1μmol L是醋酸铅引起培养海马神经细胞凋亡的最低浓度 ,各组细胞凋亡程度呈现明显的浓度依赖效应。结论 铅对发育期海马组织的损害至少部分是与铅所致神经细胞凋亡相关联的 ,并且铅导致培养海马神经细胞Brn

Objective Explore the effects of lead on the expression of Brn 3a transcription factor and the induction of apoptosis in vitro. Methods \ Experiment cell model was established using primary culture of hippocampus neurons of SD rat embryos. Target cells were exposed to lead acetate with the different concentration, i.e. 0 1,1,10,100,1000μmol/L, whilst the control group was given the same quantity of the culture medium. The survival rate was determined 24h and 48h after exposure by MTT method. Brn 3a expression and apoptosis induction were investigated by means of immunohistochemistry and TUNEL methods respectively. Results\ 1μmol/L lead acetate treatment significantly decreased the IOD of Brn 3a positive neurons( P <0 05) and 10μmol/L caused a marked decline of the rate of positive area( P <0 01) compared with the control group. In addition, 1μmol/L lead acetate was demonstrated to be the minimal concentration to induce apoptosis of cultured hippocampus neurons with a dose response effects found in higher concentrations. Conclusion\ It is indicated that the impairments of hippocampus caused by lead was at least partly related to the apoptosis induction by lead. Furthermore, decrease of Brn 3a expression followed by lead treatment might be probably one of the mechanisms to the apoptosis induced by lead in hippocampus.