重度缺氧中海马神经元KATP通道的表达改变

目的 探讨重度缺氧状态中ATP敏感性钾通道(KATP)通道在海马神经元上的表达变化. 方法 取培养1周的新生大鼠海马神经元分为4组:第1组为正常对照组,在正常氧状态中(5%CO_2、95%空气)孵育8 h;第2组为处理组,在模拟的缺氧状态(5% CO_2、95%N_2)孵育8h(单纯缺氧组);第3组为二氮嗪+缺氧组,在缺氧处理的同时添加KATP通道激动剂二氮嗪(100μmo1/L1,处理时间为8 h;第4组为甲糖宁+缺氧组,在缺氧处理的同时添加KATP通道阻断剂甲糖宁(100 μmol/L),处理时间为8h.利用MTT、免疫印迹及RT-PCR技术,比较4组细胞存活情况以及缺氧状态中神经元上KATP通道的表达改变. 结果 缺氧8h后,二氮嗪能明显降低细胞的凋亡数量,甲糖宁使细胞的凋亡数量增加,与正常对照组比较,差异均有统计学意义(P<0.05).缺氧状态中KATP通道的SUR1亚基的表达明显增加,而Kir6.2亚基表达量则无明显改变,与正常对照组比较,差异均有统计学意义(P<0.05). 结论 KATP通道的活性及表达改变,对缺氧中的海马神经元的保护起到重要作用.

Alteration of ATP-sensitive K~+ channel expression in hippocampal neurons after severe chronic hypoxia

Objective To explore the alteration of ATP-sensitive K~+(K_(ATP))channel expression in hippocampal neurons after severe chronic hypoxia. Methods The hippocampal neurons from 1-week-old rat were incubated and divided into normal control(incubated under 5%CO_2 and 95%air for 8h),hypoxia(incubated under 5%CO2 and 95%N_2 for 8h),hypoxia combined with diazoxide-treated (incubated with 100 μmol/L diazoxide under 5%CO_2 and 95%N_2 for 8h)and hypoxia combined with tolbutamide-treated groups(incubated with 100 μmol/L tolbutamide under 5%CO_2 and 95%N_2 for 8h).Cell apopmsis was identified by MTT.And the mRNA and protein expressions of K_(ATP) channel were estimated by RT-PCR and Western blot analysis.respectively. Results Hypoxia combined with diazoxide-treated group showed a significantly decreased apoptosis rate of neuron as compare with the normal control group 8h after hypoxia(P<0.05);while hypoxia combined with tolbutamide-treated group showed a significantly increased apoptosis rate of neuron compared with the normal control group(P<0.05).The expression of SUR1 in the three hypoxia groups significantly increased as compared with that in the normal control group(P<0.05);however,the expression of Kir6.2 in the three hypoxia groups did not change as compared with that in the normal control group(P>0.05).Conclusion K(ATP),channels can protect the hippocampal neurons under severe chronic hypoxia through the activation of KATP channels and upregulation of expression of KATP channels SUP1 subunit.