目的 探讨在胚胎干细胞诱导分化过程的不同阶段进行低氧处理对分化心肌细胞的影响.方法 建立胚胎干细胞向心肌细胞诱导分化的实验方法,在分化过程的不同阶段采取低氧(氧浓度为4％)处理,并设立常氧组(约为20％)作为对照,用免疫荧光鉴定分化后的心肌细胞,以流式细胞术检测低氧对分化心肌细胞的增殖、分化、凋亡的影响.结果 分化细胞经免疫荧光检测显示,部分细胞呈α辅肌动蛋白阳性(红色)、心肌肌钙蛋白I阳性(绿色)；分化细胞经流式检测显示,与常氧组相比,悬滴低氧组α-actinin阳性细胞和cTnI阳性细胞的比率分别提高了12.55％ (P ＜0.01)和6.11％(P＜0.05),悬浮低氧组凋亡比率与常氧组相比明显提高(P＜0.01),悬滴低氧组处于S期的细胞比率与常氧组相比明显降低(p＜0.01).结论 在胚胎干细胞向心肌细胞的定向诱导分化过程中,采用悬滴阶段低氧处理,使心肌特异性蛋白阳性细胞比率提高,细胞凋亡率稳定,细胞增殖能力因细胞分化成熟而有所降低,为低氧处理的最佳方案.%Objective To study the effect of nimodipine on learning and memory of rat model of Alzheimer' s disease(AD) and to explore its effect on the expression of connexin 43 (Cx 43). Methods 30 Sprague-Dawley rats were selected and randomly divided into 3 groups: control, AD, and nimodipin group. The rat AD model was established by stereotactically injecting amyloid beta protein( Aβ) 25-35 into the bilateral ventricles. Learning and memory functions were tested using the Y-type electric maze. The expression of hippocampal Cx43 was tested by western blot. Results Compared with the AD group, the number of correct reaction in Y maze increased after nimodipine treatment. Nimodipine could decreased the Cx 43 expression which was proved to be elevated in hippocampus of AD rat. Conclusion Nimodipine can improve the learning and memory ability of AD rat, which may be related to its downregulation of Cx43.
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