Objective To study the impact of sodium arsenite(NaAsO2) exposure on melanoma cells A375 (hereinafter referred to as the A375) and G361 (hereinafter referred to as the G361) pigment production and tyrosinase (TYR) activity and the differences of pigment metabolism capacity between the cell lines.Methods A375 and G361 cells were exposed to sodium arsenite at concentrations of 0.0(control),0.1 and 1.0 μmol/L for 72hours.Cell viability was measured by Alamar Blue assay.Melanin levels and TYR activity were measured at the same time.Results After exposure for 72 hours,the cells of 0.1 μmol/L dose groups of both of the two cell lines [A375:(103.32 + 1.26)％; G361:(104.10 + 1.76)％] showed a slightincrease of proliferation without significant differences compared with those of the control[A375:(100.00 ± 1.08)％; G361:(100.00 + 1.79)％,all P ＜ 0.05] ;while cell viability of the 1.0 μmol/L dose group of both of the two cell lines[A375:(75.32 ± 1.59)％; G361:(78.26 ± 2.10)％] were significantly lower than those of the control (all P ＜ 0.05).Melanin levels of G361 cell line [(7.19 ± 0.35),(7.34 ± 0.83),(8.19 ± 0.86)pg/cell] were significantly higher than that of A375[(4.35 ± 0.72),(4.54 ± 0.01),(4.60 + 0.59)pg/cell,all P ＜ 0.05] in all the three groups.TYR activity of G361 cell line [(54.13 ± 1.21),(54.56 ± 0.21),(56.25 ± 0.85)Bq] were also markedly higher than that of A375 cell[(42.00 ±0.21),(42.90 ± 0.54),(42.91 ± 0.01)Bq,all P ＜ 0.05] in all the three groups.The melanin levels and TYR activities of both of the two cells lines showed an increase tendency along with increased doses of arsenic exposure,but without significant differences when compared with those of the three groups (all P ＞ 0.05).Conclusions Arsenic related pigment disorder may be associated with increased melanin levels and TYR activities induced by arsenic exposure; individual difference of pigment metabolism may be associated with different basal melanin levels and TYR activity between different individuals.

Objective To investigate the effect of sodium fluoride(NaF) on proliferation, differentiation and the mRNA expression of osteoprotegerin (OPG) and receptor activator of nuclear factor κβ ligand (RAN KL) of mouse osteoblasts. Methods Osteoblasts were isolated from calvarias of Kunming mice born in 1 - 2 d and cultured. Various concentrations of NaF(0, 10-8, 10-7, 10-6, 10-5, 10-4, 10-3mol/L) were added to the culture medium, the proliferation and activity of alkaline phosphatase(ALP) was determined after 72 h or 120 h. The expression of OPG mRNA and RANKL mRNA was analyzed by semi-quantification RT-PCR. Difference among groups was analyzed by One-Way AN0VA. Difference between two groups was analyzed by LSD-t test. Results There was significant difference in cell proliferation among groups after 72 h(F = 13.806, P < 0.05). Compared with control group(0.434 ± 0.010) , the proliferation was significantly induced in 10-7 - 10-4 mol/L groups treated osteoblasts (0.448 ± 0.010, 0.453 ± 0.013, 0.454 ± 0.016, 0.449 ± 0.018, all P< 0.05), and was significantly suppressed in 10-3 mol/L group(0.401 ± 0.009, P < 0.05). There was statistic difference in the activity of ALP among groups(F = 9.021, P < 0.05). Compared with control group (1.677 ± 0.682), the activity of ALP significantly increased in 10-7 - 10-5 mol/L groups[ (2.447 ± 0.756) × 106, (2603 ± 0.183) × 106, (2.687 ± 0.886) × 106 U/L, P < 0.05 or P < 0.01 ] and significantly decreased in 10-4 mol/L group[ (1.479 ± 0.366) × 106 U/L, P < 0.05 ]. There was significant difference in the expression of OPG mRNA among groups(F = 11.299, P< 0.05). Compared with control group (1.000 ± 0.000), the expression of OPG mRNA was significantly increased in 10-7 - 10-4 mol/L groups( 1.058 ± 0.027, 1.053 ± 0.026, 1.088 ± 0.055, 1.069 ± 0.008, P < 0.05 or P < 0.01) , while significantly decreased in 10-3 mol/L group (0.941 ± 0.029, P< 0.05). There was no difference in RANKL mRNA expression among groups (F= 1.311, P> 0.05). The ratio of RANKL/OPG decreased with increasing doses of fluoride and increased in 10-4, 10-3 mol/L groups, but there was no difference between groups(F = 1.376, P> 0.05). Conclusions A biphasic pattern of proliferation and differentiation has been induced in mouse osteoblasts, which manifests stimulation effect in low doses and suppression in higher doses. Low doses of sodium fluoride suppress differentiation and maturation of osteoblasts by increasing expression of OPG mRNA, while high doses of sodium fluoride enhance differentiation and maturation of osteoblasts by decreasing expression of OPG mRNA.

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.

Objective To explore the effects of smoking and alcohol drinking on arsenic metabolism of people exposed to different concentrations of arsenic in drinking water.Methods Residents in Shanxi exposed to different concentrations of arsenic in drinking water and age ≥ 18 years old adults were chosen as the subjects for this study in 2008,the subjects were divided into three groups according to the concentrations of arsenic in drinking water: high-arsenic exposure group (more than 0.05 mg/L),low-arsenic exposure group (between 0.01 and 0.05 mg/L) and control group(less than 0.01 mg/L),excluded recently had eaten seafood and had poisoning symptoms of chronic arsenic in drinking water in the crowd.Smoking and alcohol drinking habits were investigated by questionnaire.Arsenic species in the urine samples were detected with hydride generation atomic absorption spectroscopy.Total arsenic(tAs) was the sum of iAs％,MMA％ and DMA％.iAs％,MMA％ and DMA％ were calculated as iAs/tAs,MMA/tAs and DMA/tAs,respectively.The first methylation ratio(FMR) and the secondary methylation ratio(SMR) were calculated as (MMA + DMA)/tAs and DMA/(MMA + DMA),respectively.Results Three hundred and ninety-five adults were chosen in this study.In the high exposure group the alcohol drinking and smoking subjects had higher MMA％(16.24％) but lower SMR(82.19％ ) than the non-drinking and non-smoking subjects (12.16％ and 86.13％,respectively).The differences of both MMA％ and SMR were significant(P ＜ 0.05 ).No significant difference was observed between the non-smoking/non-drinking subjects and the smoking or the drinking subjects(all P ＞ 0.05 ).In the low exposure group there were higher MMA％( 13.86％,13.99％) lower DMA％(72.87％,77.76％)and lower SMR (83.48％,83.90％ ) in those with smoking or drinking/smoking compared with the non-drinking and non-smoking subjects (11.83％,80.35％ and 86.54％,respectively,all P ＜0.05 ).No significant difference was observed between drinkers and non-drinking/non-smoking subjects(P ＞ 0.05).In the control group there were a higher MMA％( 17.27％,17.06％) lower DMA％ (73.89％,72.29％) and lower SMR (81.48％,82.58％ ) in those with smoking or drinking/smoking compared with the non-drinking and nonsmoking subjects( 11.52％,79.68％ and 87.19％,respectively,all P ＜ 0.05).No significant difference was observed between drinkers and the non-drinking/non-smoking subjects (all P ＞ 0.05).ConclusionThe arsenic methylation capacity of people with drinking and smoking is poorer than that of non-drinking and non-smoking subjects after arsenic exposure.

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.

Animals ; Arsenic ; toxicity ; Comet Assay ; DNA Damage ; drug effects ; Lymphocytes ; drug effects ; metabolism ; Male ; Malondialdehyde ; metabolism ; Rats ; Rats, Wistar ; Tobacco Smoke Pollution ; adverse effects

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.

Arsenites ; toxicity ; Cell Cycle ; drug effects ; Cell Division ; drug effects ; Cell Proliferation ; drug effects ; Cells, Cultured ; Dose-Response Relationship, Drug ; Humans ; Keratinocytes ; cytology ; Skin ; cytology ; Sodium Compounds ; toxicity

Objective To evaluate effects of chronic arsenic exposure and arsenic exposure time on oxidative DNA lesions in humans. Methods A cross-sectional study was conducted in 108 subjects exposed to high concentrations of arsenic in drinking water and 75 control subjects. A cohort study was conducted in 64 subjects exposed to high levels of arsenic in drinking water for 7 or 9 years. Urinary 8-oxo-7,8-dihydredeoxygnanine(8-OHdG) levels were analyzed by the enzyme-linked immunosorbent assay kit(ELISA). Urinary arsenic concentration was detected with hydride generation atomic absorption spectroscopy. Results In the cross-sectional study, the median of urinary arsenic concentration was 484.17 mg/kg Cr for the arsenic-exposed group, and 13.80 mg/kg Cr for the control group, and the difference between the two groups was statistically significant (t=32.57, P<0.01). The median of urinary 8-OHdG levels was 16.60 and 21.88 mg/kg Cr for arsenic-exposed children and adults respectively, much higher than control children(10.50 mg/kg Cr) and adults (9.11 mg/kg Cr), and the difference was statistically significant (t=5.049, 6913, all P<0.01). Urinary 8-OHdG levels were signifieandy lower for children than adults in the exposed group(t=-1.997, P<0.05). In the cohort study, the median of urinary arsenic concentration was 461.3 mg/kg Cr for the 7-year-exposed subjects and 422.90 mg/kg Cr for the 9-year-expesed subjects, and no significant difference was observed(t=-0.250, P 0.05). The median of urinary 8- OHdG levels for 9-year-exposed children and adults were 23.46 and 24.30 mg/kg Cr respectively, significantly increased compared with those of 7-year-exposed(14.29 and 18.38 mg/kg Cr), and the difference had statical signhqcanees (t= -2.949,-3.055, all P<0.01). Conclusions Chronic arsenic exposure can lead to oxidative DNA lesions in humans. The arsenic-induced DNA lesions may aggravate with the exposure time in a certain period.

ObjectiveTo study the protective effects of tert-butylhydroquinone(tBHQ) on sodium arsenite (NaAsO2)-induced cytotoxicity and oxidative injuries. Methods Chang liver cells were pretreated with tBHQ[0(control), 5, 25 μmol/L]for 24 h, and then co-treated with tBHQ(5 μmol/L) together with NaAsO2[0(control),30, 40, 50, 60 μmol/L] for another 24 h, and Alamar blue reduction rates were used to evaluate cell viability,the results were expressed as the relative ratio of Alamar blue reduction rates between the experimental group and the control group. On the other hand, Chang liver cells were pretreated with tBHQ[0(control), 5, 25 μmol/L] for24 h,and then co-treated with tBHQ(5 μmol/L) together with NaAsO2[0(control), 40, 50 μmol/L] for another 24 h,and the levels of cellular reactive oxygen species(ROS) were detected by staining cells with 2',7'-dichlorofluorescin diacetate(DCFH-DA), the results were expressed as the relative ratio of mean fluorescence intensity between the experimental group and the control group. ResultsCell viability decreased dramatically by treatment with NaAsO2(30, 40, 50, 60 μmol/L), while relieved to some extent by pretreatment with 5, 25 μmol/L tBHQ, the main effects of NaAsO2 and tBHQ, as well as their interaction were all statistically significant(F =566.57, 55.09, 14.50,all P ＜ 0.05) ; the cell viability of NaAsO2(30, 40, 50, 60 μmol/L) pretreated with tBHQ(5, 25 mol/L) were 0.75 ±0.02, 0.70 ± 0.04, 0.59 ± 0.03, 0.43 ± 0.03 and 0.75 ± 0.02, 0.73 ± 0.03, 0.65 ± 0.02, 0.50 ± 0.02, respectively,all significantly higher than corresponding NaAsO2 alone groups(0.70 ± 0.03, 0.64 ± 0.03, 0.43 ± 0.03, 0.33 ±0.01, all P ＜ 0.05), the cell viability of NaAsO2(50, 60 μmol/L) pretreated with 25 μmol/L tBHQ was higher than corresponding 5 μmol/L tBHQ pretreatment groups(all P ＜ 0.05). On the other hand, 40, 50 μmol/L of NaAsO2 significantly induced hepatocellular ROS generation, while tBHQ(5, 25 μ mol/L) pretreatment significantly decreased NaAsO2-induced intracellular ROS levels, the main effects of NaAsO2 and tBHQ, as well as their interaction were all statistically significant (F =181.78, 60.55, 4.93, all P ＜ 0.05) ; the ROS levels of NaAsO2(40, 50 μ mol/L) pretreated with tBHQ(5, 25 μmol/L) were 1.87 ± 0.09, 1.80 ± 0.07 and 1.36 ± 0.11, 1.44 ± 0.12,all significantly decreased than corresponding NaAsO2 alone groups(2.30 ± 0.18, 2.18 ± 0.17, all P ＜ 0.05),the ROS levels of NaAsO2(40, 50 μmol/L) pretreated with 25 μmol/L tBHQ decreased than corresponding 5 μmol/L tBHQ pretreatment groups (all P ＜ 0.05). ConclusiontBHQ has a certain antagonism on arsenic induced cytotoxicity and oxidative injuries.