- 學位論文
超音波刺激類澱粉乙型蛋白誘發PC-12凋亡的影響
Effects of ultrasonic stimulations on the amyloid-beta protein induced apoptosis of PC-12 cells
摘要
阿茲罕默症病患的腦部具有明顯的神經元凋亡現象，經許多研究指出，神經細胞產生凋亡反應是由毒性蛋白質--類澱粉乙型蛋白 (Amyloid-beta, Aβ) 所誘發。因此，目前許多學者採用化學或生物的方法來抑制神經元凋亡，此外，部分學者利用光照物理刺激探討此抑制效果。本研究目的為探討超音波刺激類澱粉乙型蛋白(Aβ25-35) 誘發神經細胞凋亡的反應，藉由不同超音波參數刺激神經元細胞，以觀察細胞的反應。實驗是以自製的超音波刺激器激發1MHz的換能器，產生工作週期為20%，脈衝重複頻率為1kHz，強度10 mW/cm2及50 mW/cm2、100 mW/cm2、150 mW/cm2的脈衝式超音波，刺激添加Aβ 25-35的PC-12細胞3分鐘，分別於第0、4、6、12、18、24、48小時添加MTT至細胞樣本以分析其存活與生長狀況。實驗結果顯示，經過超音波刺激的PC-12，在不同的刺激強度與時間點的統計分析上均有顯著的差異 (p < 0.05)。其中在150 mW/cm2的超音波強度刺激下，PC-12受刺激後第12小時呈現抑制細胞產生凋亡的作用。 另一方面由光學顯微鏡觀察也發現部分PC-12神經細胞初步產生分化情況。因此推測低強度超音波能夠有效抑制PC-12經Aβ25-35誘發的死亡現象，且超音波有可能使神經細胞產生分化而具有成熟神經元的能力。
並列摘要
Previous studies have shown that the effect of Amyloid-beta (Aβ) on the induction of apoptosis could lead neuronal loss to the Alzheimer’s disease. The stimulation by physical energy, such as optics, was found able to greatly diminish Aβ涐nduced apoptosis. This study is to further explore the effect of different ultrasonic energies on the neuronal cells. The experiments were carried out using such precursor neuronal cells as PC-12 which was added with Aβ25-35nof a 20 uM concentration during pre-cultured preparation. These cells were subsequently stimulated by a 20% duty cycle ultrasound of different energies ranged from 50 to 150 mW(SATA) for three minutes. The cellular response under ultrasound exposure was assessed, 7 times within 48 hours after those cells were stimulated, using the microscopic morphology, cell death measured by the typical MTT assay. Results showed that stimulations by low intensities ultrasound diminish Aβ25-35 induced apoptosis compared to those control groups, especially 150 mW(SATA), the rate of cell viability was difference between others in 12 and 18 hours after be exposured. Morphological results indicated that those cells stimulated by higher intensity ultrasounds tended to activate more differentiations in PC-12 discerned by morphological changes. This study demonstrated that the proliferation to diminish apoptosis and differentiation of neuronal cells could be regulated with the insonification of an appropriate ultrasonic intensity.