ABSTRACT
INTRODUCTION: Glucose is a simple sugar that plays an important role in energy production in biological systems. However, it has been linked to many long-term health problems including the risk of heart disease and stroke, erectile dysfunction in men and pregnancy complications in women, and damage to the kidneys, nerves, eye and vision. Also, the underlying mechanisms of diabetic complications are poorly understood. METHODS: In the present study, D-glucose-induced cytotoxic, genotoxic, and apoptotic effects were studied using MCF-7 cells as an in vitro test model. Cell viability was determined by MTT assay. Genotoxic damage was tested by the means of alkaline single cell gel electrophoresis (Comet) assay. Cell apoptosis was measured by flow cytometry assessment (Annexin-V/PI assay). RESULTS: The results of MTT assay indicated that D-glucose significantly reduces the viability of MCF-7 cells in a dose and time-dependent manner. Similar trend was obtained with the trypan blue exclusion test. Data obtained from the Comet assay indicated that D-glucose causes DNA damage in MCF-7 cells in a dose-dependent manner. The flow cytometry assessment (Annexin V FITC/PI) showed a strong dose-response relationship between D-glucose exposure and annexin V positive MCF-7 cells undergoing early apoptosis. CONCLUSION: Taking together, these data provide clear evidence that D-glucose induces cytotoxic, genotoxic, and apoptotic effects on MCF-7 cells. This finding represents the basis for further studies addressing the pathophysiological mechanisms of action of glucose overdose.
ABSTRACT
Lead toxicity has been associated with its ability to interact and damage DNA. However, its molecular mechanisms of action are not fully understood. In vitro studies in our laboratory indicated that lead nitrate (PbNO3) induces cytotoxicity and oxidative stress to human liver carcinoma (HepG2) cells in a dose-dependent manner. In this research, we hypothesized that n-acetyl-cysteine (NAC), a known antioxidant compound, affords protection against lead-induced cell death associated with genotoxic damage. To test this hypothesis, HepG2 cells were treated either with a physiologic dose of NAC, NAC plus PbNO3, or PbNO3 alone, followed by incubation in humidified 5% CO2 incubator at 37 degrees C for 48 hr. The cell viability was determined by trypan blue exclusion test. The degree of DNA damage was detected by micro gel electrophoresis (comet) assay. Our results showed that lead exposure induces a substantial cytotoxicity as well as a significant genotoxicity to HepG2 cells. However, co-treatment with a physiologic dose (500 microM) of NAC slightly increases cell viability, and significantly reduced (P < .05) the degree of DNA damage. Hence, NAC treatment may be a promising therapeutic candidate for chemoprevention against lead toxicity, based on its ability to scavenge free radicals.
