Protective Effects Of Taurine And Vitamin C On Mouse Kidney DNA Damages Exposed To As Chronically

Introduction: Arsenic (As) is a common environmental contaminant distributed worldwide. It occurs in two forms: inorganic and organic arsenic. Millions of people consumed water contaminated with arsenic in Asia, Middle and South America, etc. Arsenic exposure can result in multisystem diseases, and the kidney is a major target. As can accumulate and metabolite in the kidney, leading to acute injury. Chronic exposure can result in kidney cancer. Oxidative stress is one of the mechanisms responsible for the As related disorders. However, the exact mechanisms by which arsenic causes damage are still unknown. 8-hydroxy-2'-deoxyguanosine (8-OH-dG) is produced by reactive oxygen species. Therefore, 8-OH-dG is a specific and sensitive biomarker of oxidative DNA damage. 8-OH-dG was not reported in As-induced kidney injury.Methods:60 mice were divided into 6 groups with 10 for each, low dose group (1 ppm As2O3) , medium dose group(2 ppm As2O3), high dose group (4 ppm As2O3), taurine protective group (4 ppm As2O3+150 mg/kg taurine), vitamin C protective group (4 ppm As2O3+45 mg/kg vitamin C), and distilled water group as control. The two prophylactics were administered twice per week intragastrically. As2O3 was given ad libitum in water for 60 days, after that mice were sacrificed. Kidneys were taken and performed with HE staining, and 8-OH-dG expressions were examined by immunohistochemistry.Total optical densities (OD) were expressed as mean±SD, and the significance of the differences between mean values was determined by one-way analysis of variance (ANOVA). Statistical Package for Social Sciences 11.5 (SPSS 11.5) computer package was used for multiple comparisons. Differences were considered significant at p<0.05.Results: The kidney cells in As treated groups showed swelling, vacuolation, nuclear breakage, lysis, vasodilation and congestion. Proximal convoluted tubules were more severely damaged than glomeruli. 8-OH-dG was also strongly expressed in As exposed groups(OD of low dose group:926.33±298.01;OD of medium dose group:1654.2±571.02;OD of high dose group:5522.7±686.34; OD of control group: 4.9412±1.6743, P<0.01). Two prophylactic groups showed very mild damages with very low 8-OH-dG level(OD of taurine protective group:25.833±5.9016;OD of vitamin C protective group:23.320±12.121, P<0.01).Conclusions: The kidneys showed severe pathologic injuries and DNA oxidative damages after long-term As exposure. Taurine and vitamin C alleviated the damages significantly.