Objective The aim of this study is to investigate whether microwave exposure would affect the N-methyI-D-aspartate receptor （NMDAR） signaling pathway to establish whether this plays a role in synaptic plasticity imp...Objective The aim of this study is to investigate whether microwave exposure would affect the N-methyI-D-aspartate receptor （NMDAR） signaling pathway to establish whether this plays a role in synaptic plasticity impairment. Methods 48 male Wistar rats were exposed to 30 mW/cm^2 microwave for 10 min every other day for three times. Hippocampal structure was observed through H＆E staining and transmission electron microscope. PC12 cells were exposed to 30 mW/cm^2 microwave for 5 min and the synapse morphology was visualized with scanning electron microscope and atomic force microscope. The release of amino acid neurotransmitters and calcium influx were detected. The expressions of several key NMDAR signaling molecules were evaluated. Results Microwave exposure caused injury in rat hippocampal structure and PC12 cells, especially the structure and quantity of synapses. The ratio of glutamic acid and gamma-aminobutyric acid neurotransmitters was increased and the intracellular calcium level was elevated in PC12 cells. A significant change in NMDAR subunits （NR1, NR2A, and NR2B） and related signaling molecules （CaZ＋/calmodulin-dependent kinase II gamma and phosphorylated cAMP-response element binding protein） were examined. Conclusion 30 mW/cm^2 microwave exposure resulted in alterations of synaptic structure, amino acid neurotransmitter release and calcium influx. NMDAR signaling molecules were closely associated with impaired synaptic plasticity.展开更多
目的探讨不同条件微波辐射对PC12细胞的损伤效应,为深入研究微波辐射的损伤机制提供剂量学依据。方法采用平均功率密度(重复频率×脉宽)分别为10 m W/cm2(100 pps$500 ns)、30 m W/cm2(300 pps$500 ns)和30 m W/cm2(1000 pps$150 ns...目的探讨不同条件微波辐射对PC12细胞的损伤效应,为深入研究微波辐射的损伤机制提供剂量学依据。方法采用平均功率密度(重复频率×脉宽)分别为10 m W/cm2(100 pps$500 ns)、30 m W/cm2(300 pps$500 ns)和30 m W/cm2(1000 pps$150 ns)的微波辐射NGF诱导后的PC12细胞5 min,于辐射后6 h,采用流式细胞术检测细胞周期、凋亡和坏死率,采用激光扫描共聚焦显微镜观察细胞凋亡和坏死率,采用透射电镜观察PC12细胞超微结构的改变。结果10 m W/cm2(100 pps$500 ns)辐射后6 h,G0-G1期PC12细胞数减少(p<0.05),G2-M期细胞数增加(p<0.01);30 m W/cm2(1000 pps$150 ns)辐射后6 h,G0-G1期细胞数增加(p<0.05),G2-M期减少(p<0.01);30 m W/cm2(300 pps$500 ns)辐射后6 h,G0-G1期细胞数增加(p<0.05),S期细胞数减少(p<0.01),细胞凋亡率增加(p<0.01),PC12细胞核膜间隙增宽,染色质浓缩边集,核仁呈蜂窝状;线粒体肿胀、空化。结论 30 m W/cm2(300 pps$500 ns)微波辐射可引起PC12细胞生长抑制,凋亡率增加,结构损伤;30 m W/cm2(300 pps$500 ns)可作为深入研究微波辐射的损伤机制的辐射剂量。展开更多
BACKGROUND： Cyclophilin A can protect neurons against oxidative stress. OBJECTIVE： To investigate the effect of cyclophilin A on Bcl-2 and Bax protein expression in pheochro-mocytoma （PC12） cells treated with beta...BACKGROUND： Cyclophilin A can protect neurons against oxidative stress. OBJECTIVE： To investigate the effect of cyclophilin A on Bcl-2 and Bax protein expression in pheochro-mocytoma （PC12） cells treated with beta-amyloid fragment 25-35 （Aβ25-35）, and to verify the protection pathway of cyclophilin A. DESIGN, TIME AND SETTING： The initial experiment was performed at the Laboratory of Department of Neurology, First Clinical College, China Medical University from November 2006 to July 2007. MATERIALS： PC12 cells were cultured at the Cell Center of Peking Union Medical College. Aβ25-35 （Sigma, USA）, antibodies of Bcl-2 and Bax （Wuhan Boster, China）, and recombinant human cyclophilin A （Biomol, USA） were used in this study. METHODS： PC12 cells were divided into three groups. Cells in the control group were incubated in culture medium. Cells in the Aβ25-35 injury group were incubated in medium containing a final concentration of 10 μmol/L of Aβ25-35. Cells in the cyclophilin A group were incubated in medium containing a final con-centration of 10 nmol/L of cyclophilin A for 30 minutes, and then treated with 10 μmol/L Aβ25-35. MAIN OUTCOME MEASURES： After 24 hours of culture, immunohistochemistry was used to detect Bcl-2 and Bax expression in PC12 cells. Annexin-V flow cytometry was employed to measure the apoptosis rate of PC12 cells. The MTT method was applied to examine the survival rate of PC12 cells. RESULTS： Bcl-2 expression decreased, whereas Bax expression increased in PC12 cells treated with Aβ25-35 （t = 2.277, 5.957, P 〈 0.05）. However, in PC12 cells treated with Aβ25-35 and cyclophilin A, Bcl-2 expression increased and Bax expression decreased （t = 4.497, 2.531, P 〈 0.05）. The survival rate of PC12 cells significantly decreased and the apoptosis rate increased （t=8.509, 22.886, P 〈 0.05） following Aβ25-35 treatment. Cyclophilin A enhanced the survival rate of PC12 cells to Aβ25-35-induced apoptosis （t = 4.895, 10.042, P 〈 0.05）. CONCLUSION： Cyclophilin A can increase Bcl-2 expression and decrease Bax expression in PC12 cells treated with Aβ25-35, which indicates that cyclophilin A has a protective effect on Aβ25-35-induced injury to PC12 cells.展开更多
基金supported by the National Natural Science Foundation of China(No.81172620)
文摘Objective The aim of this study is to investigate whether microwave exposure would affect the N-methyI-D-aspartate receptor （NMDAR） signaling pathway to establish whether this plays a role in synaptic plasticity impairment. Methods 48 male Wistar rats were exposed to 30 mW/cm^2 microwave for 10 min every other day for three times. Hippocampal structure was observed through H＆E staining and transmission electron microscope. PC12 cells were exposed to 30 mW/cm^2 microwave for 5 min and the synapse morphology was visualized with scanning electron microscope and atomic force microscope. The release of amino acid neurotransmitters and calcium influx were detected. The expressions of several key NMDAR signaling molecules were evaluated. Results Microwave exposure caused injury in rat hippocampal structure and PC12 cells, especially the structure and quantity of synapses. The ratio of glutamic acid and gamma-aminobutyric acid neurotransmitters was increased and the intracellular calcium level was elevated in PC12 cells. A significant change in NMDAR subunits （NR1, NR2A, and NR2B） and related signaling molecules （CaZ＋/calmodulin-dependent kinase II gamma and phosphorylated cAMP-response element binding protein） were examined. Conclusion 30 mW/cm^2 microwave exposure resulted in alterations of synaptic structure, amino acid neurotransmitter release and calcium influx. NMDAR signaling molecules were closely associated with impaired synaptic plasticity.
文摘目的探讨不同条件微波辐射对PC12细胞的损伤效应,为深入研究微波辐射的损伤机制提供剂量学依据。方法采用平均功率密度(重复频率×脉宽)分别为10 m W/cm2(100 pps$500 ns)、30 m W/cm2(300 pps$500 ns)和30 m W/cm2(1000 pps$150 ns)的微波辐射NGF诱导后的PC12细胞5 min,于辐射后6 h,采用流式细胞术检测细胞周期、凋亡和坏死率,采用激光扫描共聚焦显微镜观察细胞凋亡和坏死率,采用透射电镜观察PC12细胞超微结构的改变。结果10 m W/cm2(100 pps$500 ns)辐射后6 h,G0-G1期PC12细胞数减少(p<0.05),G2-M期细胞数增加(p<0.01);30 m W/cm2(1000 pps$150 ns)辐射后6 h,G0-G1期细胞数增加(p<0.05),G2-M期减少(p<0.01);30 m W/cm2(300 pps$500 ns)辐射后6 h,G0-G1期细胞数增加(p<0.05),S期细胞数减少(p<0.01),细胞凋亡率增加(p<0.01),PC12细胞核膜间隙增宽,染色质浓缩边集,核仁呈蜂窝状;线粒体肿胀、空化。结论 30 m W/cm2(300 pps$500 ns)微波辐射可引起PC12细胞生长抑制,凋亡率增加,结构损伤;30 m W/cm2(300 pps$500 ns)可作为深入研究微波辐射的损伤机制的辐射剂量。
文摘BACKGROUND： Cyclophilin A can protect neurons against oxidative stress. OBJECTIVE： To investigate the effect of cyclophilin A on Bcl-2 and Bax protein expression in pheochro-mocytoma （PC12） cells treated with beta-amyloid fragment 25-35 （Aβ25-35）, and to verify the protection pathway of cyclophilin A. DESIGN, TIME AND SETTING： The initial experiment was performed at the Laboratory of Department of Neurology, First Clinical College, China Medical University from November 2006 to July 2007. MATERIALS： PC12 cells were cultured at the Cell Center of Peking Union Medical College. Aβ25-35 （Sigma, USA）, antibodies of Bcl-2 and Bax （Wuhan Boster, China）, and recombinant human cyclophilin A （Biomol, USA） were used in this study. METHODS： PC12 cells were divided into three groups. Cells in the control group were incubated in culture medium. Cells in the Aβ25-35 injury group were incubated in medium containing a final concentration of 10 μmol/L of Aβ25-35. Cells in the cyclophilin A group were incubated in medium containing a final con-centration of 10 nmol/L of cyclophilin A for 30 minutes, and then treated with 10 μmol/L Aβ25-35. MAIN OUTCOME MEASURES： After 24 hours of culture, immunohistochemistry was used to detect Bcl-2 and Bax expression in PC12 cells. Annexin-V flow cytometry was employed to measure the apoptosis rate of PC12 cells. The MTT method was applied to examine the survival rate of PC12 cells. RESULTS： Bcl-2 expression decreased, whereas Bax expression increased in PC12 cells treated with Aβ25-35 （t = 2.277, 5.957, P 〈 0.05）. However, in PC12 cells treated with Aβ25-35 and cyclophilin A, Bcl-2 expression increased and Bax expression decreased （t = 4.497, 2.531, P 〈 0.05）. The survival rate of PC12 cells significantly decreased and the apoptosis rate increased （t=8.509, 22.886, P 〈 0.05） following Aβ25-35 treatment. Cyclophilin A enhanced the survival rate of PC12 cells to Aβ25-35-induced apoptosis （t = 4.895, 10.042, P 〈 0.05）. CONCLUSION： Cyclophilin A can increase Bcl-2 expression and decrease Bax expression in PC12 cells treated with Aβ25-35, which indicates that cyclophilin A has a protective effect on Aβ25-35-induced injury to PC12 cells.
