AIM: To study the effects of hydrogen peroxide on mitochondrial gene expression of intestinal epithelial cells in in vitro model of hydrogen peroxide-stimulated SW-480 cells.
METHODS: RNA of hydrogen peroxide-induced SW-480 cells was isolated, and reverse-transcriptional polymerase chain reaction was performed to study gene expression of ATPase subunit 6, ATPase subunit 8, cytochrome c oxidase subunit I (COI), cytochrome coxidase subuit II (COII) and cytochrome c oxidase subunit III (COIII). Mitochondria were isolated and activities of mitochondrial cytochrome c oxidase and ATPase were also measured simultaneously.
RESULTS: Hydrogen peroxide led to differential expression of mitochondrial genes with some genes up-regulated or down-regulated in a dose dependent manner. Differences were very obvious in expressions of mitochondrial genes of cells treated with hydrogen peroxide in a concentration of 400 μmol/L or 4 mmol/L. In general, differential expression of mitochondrial genes was characterized by up-regulation of mitochondrial genes in the concentration of 400 μmol/L and down-regulation in the concentration of 4 mmol/L. In consistence with changes in mitochondrial gene expressions, hydrogen peroxide resulted in decreased activities of cytochrome c oxidase and ATPase.
CONCLUSION: The differential expression of mitochondrial genes encoding cytochrome c oxidase and ATPase is involved in apoptosis of intestinal epithelial cells by affecting activities of cytochorme c oxidase and ATPase.