朊蛋白106-126肽段对分化后PC12细胞的凋亡作用

目的：研究朊蛋白106-126肽段在细胞水平上的毒性作用。 方法：PC12细胞常规培养后加入神经生长因子（NGF）诱导成神经元样细胞，再加入朊蛋白106-126肽段，MTT法检测细胞存活率，同时观察细胞生长和形态变化，通过形态学改变、流式细胞术和DNA电泳检测细胞凋亡。 结果：细胞接触肽段后存活率下降28.9％；光镜下可见细胞贴壁不良，胞体缩小，细胞突起断裂缩短；荧光染色可见细胞突起缩短、胞核固缩、胞质染成橘红色的凋亡细胞；电镜下可见胞质中出现空泡样结构，细胞染色质浓集于核膜内侧并裂解成碎块状；流式细胞仪检测细胞出现亚二倍体峰，DNA电泳出现梯状带。 结论：朊蛋白106-126肽段能够诱导分化后的PC12细胞凋亡，具有明确的毒性作用。利用106-126肽段感染分化的PC12细胞可能是在细胞水平上研究朊蛋白毒性作用的理想模型。

Apoptosis of differentiated PC12 cell induced by prion protein 106-126 peptide

Objective To investigate the effects of prion protein 106-126 peptide on inducing apoptosis in differentiated PC12 cells. Methods After differentiated by nerve growth factor (NGF), the PC12 cells were infected by prion protein 106-126 peptide. Cell viability was determined by using the MTT assay and the morphological changes were observed. Apoptotic was detected by morphological changes, DNA electrophoresis and flow cytometry. Results Infected by this peptide, cell viability decreased 28.9%. Under light microscope, cells were shrinked and rounded, many cells were divorced from plate wall, some neuraxon shortened and broke. Apoptotic cells which nucleolus shrinked and rounded could be coloured orange by fluorescent colouration. Under electron microscope, chromatin gathered along the inside of the nuclear membrane, vacuole bodies appeared. Apoptotic peak was detected by flow cytometry and the ladder band appeared in DNA electrophoresis. Conclusion Prion protein 106-126 peptide can induce apoptosis in differentiated PC12 cells and present cellular toxicity definitely. It might be a perfect model to study the cellular toxicity of prion protein.