title: Germanium dioxide induces mitochondria-mediated apoptosis in Neuro-2A cells.
abstract: Germanium (Ge) is commonly used in the semiconductor industry as well as health-promoting and medical field. Biologically, germanium possesses erythropoietic, anti-microbial, anti-tumor, anti-amyloidosis, and immunomodulative effects. However, toxic effects of Ge-containing compounds on kidney, muscle, neuronal cells, and nerves have been reported. Mitochondrial dysfunction was found to be involved in the pathogenesis of GeO(2)-induced nephropathy and myopathy. Since it is well known that mitochondria play a major role in apoptosis triggered by many stimuli, an effort was made to examine whether the Ge-induced neurotoxicity occurs through mitochondria-mediated apoptosis. A mouse neuroblastoma cell line, Neuro-2A, was used in the present study. After incubating with 0.1-800microM of GeO(2) for 0-72h, the cell viability of Neuro-2A cells was inhibited in a dose- and time-dependent manner. Further analysis showed that aside from the changes in the nuclear morphology responsible for apoptosis, the release of cytochrome c, the loss of mitochondrial membrane potential, the translocation of Bax, and the reduction of Bcl-2 expression were also observed in Neuro-2A cells after GeO(2) treatment. These results indicate that the mitochondria-mediated apoptosis is involved in this in vitro model of GeO(2)-induced neurotoxicity.
authors.affiliation: Department of Physiology, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
authors.forename: Chuang-Hao
authors.initials: CH
authors.lastname: Lin
authors.forename: Shun-Sheng
authors.initials: SS
authors.lastname: Chen
authors.forename: Yen-Chun
authors.initials: YC
authors.lastname: Lin
authors.forename: Yu-Shan
authors.initials: YS
authors.lastname: Lee
authors.forename: Tsan-Ju
authors.initials: TJ
authors.lastname: Chen
mesh_terms: D000165:Acridine Orange; D000704:Analysis of Variance; D000818:Animals; D016587:Antimutagenic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D045304:Cytochromes c / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004996:Ethidium; D005434:Flow Cytometry / Q000379:methods; D005857:Germanium / Q000494:pharmacology*; D007150:Immunohistochemistry / Q000379:methods; D020287:In Situ Nick-End Labeling / Q000379:methods; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D051379:Mice; D008928:Mitochondria / Q000187:drug effects*; D009447:Neuroblastoma; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D013997:Time Factors; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: D016587:Antimutagenic Agents; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D005857:Germanium; C040516:germanium oxide; D045304:Cytochromes c; D004996:Ethidium; D000165:Acridine Orange