Effects of sub-chronic arsenic exposure on arsenic exposure markers and brain total NOS activity in rats / 中华地方病学杂志

ABSTRACT

Objective To observe the changes of the totle nitric oxide synthase (NOS) activity in brain tissue,the metabolism of arsenic speciations in urine and the totle contents in blood,brain after rats drinking water containing different doses of arsenic.Methods Forty SD rats were divided into 4 groups according to random number table,10 rats in each groupcontrol group,5 mg/L NaAsO2 group,10 mg/L NaAsO2 group and 50 mg/L NaAsO2 group.The animals were allowed free access to water and food.Body mass was weighted once a week.Expose to arsenic was continued for three months,then the animals were put to death and their blood,urine and brain tissues were collected.Determination of four kinds of speciations of arsenic (3 valence inorganic arsenic,iAs3+;5 valence inorganic arsenic,iAs5+;monomethylated arsenic,MMA;dimethylated arsenic,DMA) in urine was carried out by high performance liquid chromatography-hydride atomic fluorescence spectrometry.Total arsenic concentration in blood and brain tissue was detected by Atomic Fluorescence Spectrometry.The activity of total NOS in blood and brain tissue was detected using the spectrophotometer method.Results ①Weightat the 5th-12th week after arsenic exposure,compared with the weight of control group [(420.93 ± 21.13),(441.52 ± 28.85),(462.45 ± 30.57),(470.16 ± 31.17),(484.92 ± 32.93),(483.79 ± 29.63),(482.02 ± 29.14),(483.89 ± 29.31) g],weight of rats in 50 mg/L NaAsO2 group [(391.66 ± 32.88),(410.17 ± 33.47),(426.96 ± 33.49),(427.15 ± 32.20),(441.78 ± 33.69),(438.27 ± 33.05),(440.98 ± 33.33),(441.46 ± 32.45) g] was significantly lighter (all P ＜ 0.05).② Urine arsenicthe medians of iAs3+ content (0.00,57.30,236.33,857.80 μg/L) were compared between control group,5,10 and 50 mg/L NaAsO2 groups,the differences were statistically significant (x2 =31.982,P ＜ 0.01);the medians of iAs5+ content (0.00,0.00,80.75,162.90 μg/L) were compared between control group,5,10 and 50 mg/L NaAsO2 groups,the differences were statistically significant (x2 =24.206,P ＜ 0.01);the medians of DMA content (12.83,1 711.13,l0 386.20,37 038.90 μg/L) were compared between control group,5,10 and 50 mg/L NaAsO2 groups,the differences were statistically significant (x2 =34.338,P ＜ 0.01).③Blood arsenictotal arsenic content in serum of rats [(5.04 ± 1.57),(25.40 ± 7.33),(32.28 ± 7.75),(56.11 ± 19.87) mg/L] was compared between control group,5,10 and 50 mg/L NaAsO2 groups,the differences were statistically significant (F =27.78,P ＜ 0.05).④Brain arsenictotal arsenic content in brain tissue of 5,10 and 50 mg/L NaAsO2 groups [(0.57 ± 0.20),(1.56 ± 0.52),(3.63 ± 0.48) μg/g] was respectively compared with that of control group [(0.11 ± 0.06) μg/g],the differences were statistically significant (all P ＜ 0.05).⑤NOS activitycompared with control group [(27.69 ± 5.56) kU/L],total NOS activity [(33.63 ± 2.26),(34.19 ± 2.55) kU/L] in serum of rats in 10 mg/L NaAsO2 group and 50 mg/L NaAsO2 group increased significantly (all P ＜ 0.05);compared with control group [(1.79 ± 0.79) U/(mg·prot)],total NOS activity [(2.63 ± 0.60)U/(mg ·prot)] in brain tissue of 50 mg/L NaAsO2 group increased significantly (P ＜ 0.05).Conclusions A high dose of arsenic exposure can increase totle contents of arsenic in blood,brain and the activity of total NOS in rat brain tissue.