Description:
<jats:sec><jats:label /><jats:p>The objective of this study was to determine the physiological effects of low‐dose hydrogen peroxide (H2O2) treatments on the cellular physiology of GM00701, GM01354, GM01385, MRC‐5, and MRC‐9 human diploid fibroblast cell lines. A number of published reports have shown short‐term treatments of fibroblasts with H2O2 concentrations of 100 uM to 200 uM result in apoptosis. However, our preliminary studies show that 5.0 uM to 25.0 uM concentrations of H2O2 are capable of inducing apoptosis in the cell lines that were studied. One‐hour treatments of fibroblasts with these H2O2 concentrations were shown to result in statistically significant decreases in cell number. The relative cell numbers are measured 24 hours after treatment by Alamar Blue cytotoxicity assay. We also used flow cytometry to analyze the effects of H2O2 treatment on cell cycle progression in a time‐dependent manner 12 and 24 hours post‐treatment. We find a 1.5‐ to 3‐fold increase in sub G1 cells 24 hours after treatment when compared to untreated cells. The results are cell line specific. To confirm these findings, studies are currently underway to assess the effects of H2O2 treatment on intracellular reduced GSH concentrations and Poly (ADP‐ribose) polymerase (PARP) cleavage. We will assess the effects of sub‐lethal doses of H2O2 on the metabolism of low density lipoprotein (LDL) and oxidized low density lipoprotein (ox‐LDL) by flow cytometry. We will also assess the effects of sub‐lethal doses of H2O2 on cytokine‐induced IL‐6 and MCP‐1 secretion by ELISA. From our studies, we conclude that low levels of oxidative stress can have significant effects on the physiology of human fibroblasts.</jats:p></jats:sec>