ABSTRACT
Objective To observe the distribution and metabolism of arsenic speciation in urine of rats exposed to different concentrations of dimethylaraenic acid (DMA) through drinking water.Methods Thrity six weaning Wistar rats were randomly divided into normal control,low-dose group and high-dose group,12 rats in each group(6 female and 6 male); average body weight of female rats was (60 ± 5)g,and male rats was (50 ± 5)g.All rats of the 3 groups were given DMA at concentrations of 0,100,200 mg/L,respectively,corresponding to their specific groups through drinking water for 10 weeks.Inorganic arsenic(iAs),monomethylarsenic acid(MMA),DMA and trimethylarsenic compound (TMA) in urine were measured by hydride generation trapping and ultrahypothermia coupled with atomic absorption spectrometry.Results After feeding for 10 weeks,the differences of rat urinary concentrations of iAs,MMA,DMA and TMA between normal control,low-dose group and high-dose group were statistically significant(x2 =25.441,25.942,25.751,17.767,all P＜ 0.01).Urinary concentrations of iAs,MMA and DMA(2.541,4.383,24.447 mg/L) of low-dose group were significant higher than those of normal control (0.784,0.000,0.743 mg/L,all P ＜ 0.05) ; iAs,MMA,DMA and TMA(3.978,7.186,35.112,4.518 mg/L) of high-dose group were significantly higher than those of normal control(0.784,0.000,0.743,0.000 mg/L,all P ＜ 0.05).The concentrations increased along with increasing doses of DMA concentrations in drinking water(all P ＜ 0.05).Conclusions After rats are exposed to DMA,most of the DMA are excreted in unchanged form in urine and a small portion of DMA is metabolized into TMA.
ABSTRACT
ObjectiveTo study the state of oxidative injury induced by sodium arsenite(NaAsO2) in SV-40-immortalized normal uroepithelial (SV-HUC-1 ) cells.Methods SV-HUC-1 cells were exposed to different concentrations of NaAsO2[0(control),1,2,4,8,10 μmol/L] for 24 h,intracellular reactive oxygen species (ROS) was determined by flow cytometry,and the content ofintracellular nitrotyrosine(NT) and the 8-Hydroxydeoxyguanosine (8-OHdG) levels of cell culture medium were detected by enzyme linked immunosorbent assay (ELISA).Results After 24 h treatment,ROS levels(81.76 ± 4.91,95.23 ± 2.17,126.61 ± 17.95,126.74 ± 27.77,114.18 ± 9.65) of SV-HUC-1 cells in the 1,2,4,8,10 μmol/L NaAsO2 exposure groups were significantly higher than those of the control group (69.84 ± 1.28,P ＜ 0.05 or ＜ 0.01 ),ROS levels and exposure dose were positively correlated significantly(r =0.818,P＜ 0.01); the content of NT in the 10 μmol/L NaAsO2 exposure group[(919.66 ± 206.33) μg/L] was significantly higher than that in the control group[ (238.19 ± 38.28)μg/L,P ＜ 0.01 ],NT content and dye concentrations of arsenic also had dose-response relationship (r =0.617,P ＜ 0.01); after 24 h the cells were treated with arsenic,no significant difference of 8-OHdG content in the culture medium was observed(F =2.127,P ＞ 0.05 ).ConclusionNaAsO2 can cause SV-HUC-1 cell oxidative damage.
ABSTRACT
Objective To observe the metabolism and distribution of arsenic in liver and brain of offspring rata by exposure to arsenic of pregnant rats or lactation dams and weaned pups,and explore if arsenic could penetrate the placental barrier,lactation barrier and blood brain barrier. Methods The Wistar female rots were randomly divided into four groups according to body weights,12 in each group,and were fed with drinking water that contained arsenic(NaAsO_2) 0,10,50,100 mg/L beginning from the gestafional day 6 until pups 42 days old. Pups were separately sacrificed on postnatal day(PND) 0,15,28,42. Arsenic in liver and brain of offspring rots and in breast milk was examined by atomic absorption speetrophotometer with an arsenic speeiation pretreatment system. Results Concentration of iAs,MMA,DMA of brain in 50,100 mg/L groups were higher than that of 0 mg/L group[0,0,0,(7.3±6.6),0,(44.2±27.4)ng/g]on PND 0,42[iAs: (120.0±46.0),(195.5±125.3),(216.5±278.4),(176.6±151.8) ng/g; M MA: (47.2±18.1),(199.6±389.1),(47.4±55.2),(82.7±79.2) ng/g; DMA: (984.3±377.4),(2222.1±1433.2),(998.1±368.3),(1781.3±715.7)ng/g,all P < 0.05]. Concentration of DMA of brain in 50,100 mg/L groups were higher than that of 0 mg/L group[(13.9±18.1),(50.6±98.3)ng/g]on PND 15,28 [(270.3±73.1),(323.9±72.7),(758.7±245.9),(1020.6±383.6) ng/g,all P < 0.05]. Concentration of iAs,DMA of liver in 10,50,100 mg/L groups were higher than that of 0 mg/L group [(1.4±3.5),(49.7± 47.1),0,(100.4±30.2)ng/g]on PND 28,42 [iAs: (37.5±28.1),(268.8±246.4),(307.2±339.9),(15.4±9.4),(479.1±161.1),(408.4±51.9)ng/g;DMA: (594.5±148.8),(3181.9±519.0),(4834.2±2568.4),(1061.8± 85.2),(3697.1±553.7),(4120.0±732.8) ng/g,all P < 0.05]. Concentration of DMA of liver in 10,50,100 mg/L groups were higher than that of 0 mg/L group[(13.2±20.5)ng/g]on PND 15[(182.0±60,2),(637.6±90.0),(1458.7±196.3)ng/g,all P < 0.05]. Concentration of arsenicals of liver and brain showed a dose-dependent increase. The concentrations of DMA of breast milk in 50,100 mg/L groups were also higher than that of 0 mg/L group[(9.8±13.4),0 ng/g]on PND 0,15 [(182.3±85.9),(372.2±203.9),(124.2±33.1),(244.4±196.5)ng/g,all P < 0.05]. In the analysis of the change of arsenic on different postnatal day,we found the concentration of iAs,MMA,DMA,TMA in liver and brain of pups all decreased on postnatal day 15,and was lower than that on PND 0,28 and 42. Conclusions The distribution of arsenic and methyl-metabolism in liver and brain of pups is related with arsenic exposure dose. Arsenic can penetrate the placenta and blood brain barrier easily and lactation can hinder arsenic intake in some extent.