| 摘要: | H2O2 (Hydrogen peroxide)廣泛用於美白試劑，H2O2不僅為美白成分，同時也為氧化性物質，而氧化性物質被認為雙重角色，亦會造成自由基與抗氧化平衡失調。
根據J. A. ImLa文獻指出，氧化性物質濃度於1~3mM可誘導SOS修復系統來保護細胞，而嚴重暴露氧化性物質之結果則會產生凋亡反應。在我們過去實驗室C.H Chiu之研究數據，觀察到人類口腔細胞 (hNOK)暴露H2O2會造成細胞死亡，核DNA氧化損傷，mtDNA4977缺失和線粒體膜電位之變化。過量的H2O2促進牙齒漂白，但也造成的細胞損傷。為了達到牙齒美白且快速清除H2O2造成的氧化壓力，故本研究目的是將hNOK暴露H2O2，並以二維膠電泳 (two-dimensional gel electrophoresis, 2D-GE) 顯示受到暴露後細胞內蛋白質量的變化情形及利用西方墨點法探討粒線體內蛋白質(ND4、ND5、ND6和COII)之變化。二維膠片影像，利用軟體分析後有變化的蛋白質再利用質譜分析得到這些蛋白質身分鑑定，作為口腔細胞對過量的H2O2造成的氧化壓力找出預防方法。
Hydrogen peroxide (H2O2) is predominate component for Dental bleaching agents. H2O2 is not only an active bleaching component but also acts as a reactive oxygen species (ROS). ROS, which is considered as dual role, depends on the imbalance between antioxidants and free radicals. In that, in J. A. ImLay articles cited that Mode I ROS dosage (1~3mM) induced SOS response to protect cells; under severe ROS exposure results in apoptotic response.
In our previous data from C.H Chiu research observed the phenomena regarding to hNOK cell death, nuclear DNA oxidative damage, mtDNA4977 deletion and mitochondrial membrane potential change under exposure to H2O2.
It suggested that the function of overdose H2O2 was paradoxical. They promoted tooth-bleaching, but caused cellular damage. In order to of achieve tooth-bleaching and remove quickly H2O2 mediated oxidative stress, this work is that investigate the proteomic regulation in hNOK. The differences in the levels of proteins extracted from hNOK cells with and without exposure to H2O2, were investigated using two-dimensional gel electrophoresis (2D-GE) display and western blot to investigate the mitochondrial DNA of the proteins (ND4, ND5, ND6 and CO II ).
First, we identified 17 and 22 proteins from the comparison between 2D-GE maps with H2O2 or control in dose and time manner respectively. The down-regulation of cytoskeleton proteins may cause the cytoskeletal dissociation in time. The differential proteins of cyclophilin, TPC-1 subunit delta, annexin A2, calmodulin like protein 3 participate in early apoptotic stage under exposure to H2O2. Low dose of H2O2 induce ND5, COII and ND4, ND6 over-expression in seven and four day respectively. Expression decreased after the peak time in addition to ND6.Comprehensive experimental results, the dental bleaching agent can cause damage whether apoptosis is not clear. |
