谷胱甘肽与亚硒酸钠对饮水砷暴露小鼠体内砷代谢的影响

目的 探讨给予外源性谷胱甘肽(GSH)和亚硒酸钠(sodium selenite)对饮水砷暴露小鼠肝、肾和血中砷代谢的影响.方法 将小鼠按数字表法随机分为对照组、单纯染砷组(砷组)、GSH干预组(GSH组)与亚硒酸钠干预组(硒组),每组各8只小鼠.小鼠以自由饮水方式共染砷4周,饮水砷浓度为50 mg/L.从第4周起,染砷同时腹腔注射GSH(600 mg/kg体重)或亚硒酸钠(1 mg/kg体重)进行干预,共干预7 d.末次注射后处死小鼠,取其肝、肾和血组织样品.采用氢化物发生-超低温捕集-原子吸收分光光度法,分别检测小鼠肝、肾和血中无机砷(iAs)、一甲基胂(MMA)和二甲基胂(DMA)的含量.结果 GSH组小鼠肝中DMA含量(233.76±60.63)ng/g湿重]及血中DMA含量(88.52±30.86)ng/g湿重]和总砷(TAs)含量(162.32±49.45)ng/g湿重]高于相对应的砷组小鼠(218.36±42.71)、(45.32±12.19)、(108.51±18.00)ng/g湿重](q值分别为3.06、6.40、10.72,P＜0.05).GSH组小鼠肝中砷一甲基化率(PMI,0.65±0.05)和二甲基化率(SMI,0.55±0.05)及血中PMI(0.85±0.07)与砷组小鼠相对应的甲基化率(0.58±0.06、0.44±0.09、0.54±0.11)比较升高(q值分别为3.75、5.26、4.21.P＜0.05).硒组与砷组各项指标间差异无统计学意义.结论 给予外源性GSH可以促进iAs在小鼠体内甲基化代谢,从而降低其对机体的毒性损伤.而亚硒酸钠则无明显作用.

Effect of glutathione and sodium selenite on the metabolism of arsenic in mice exposed to arsenic through drinking water

Objective To explore the effect of glutathione(GSH)and sodium selenite on the metabolism of arsenic in the liver,kidney and blood of mice exposed to iAsⅢ through drinking water.Methods The mice were randomly divided into control,arsenic,GSH and sodium selenite group,respectively.And each group had eight mice and the mice were exposed to 50 mg/L arsenite by drinking water for 4 weeks.Mice were intraperitoneally injected with GSH(600 mg/kg)and sodium selenite (1 mg/kg)for seven days from the beginning of the fourth week.At the end of the fourth week,liver,kidney and blood were samplod to assess the concentrations of inorganic arsenic(iAs),monomethylarsenic acid(MMA),dimethylarsenic acid(DMA)by hydride generation trapping by ultra-hypothermia coupled with atomic absorption spectrometry.Results The liver DMA(233.76±60.63 ng/g)concentration in GSH group was significantly higher than the arsenic group(218.36±42.71 ng/g).The concentration of DMA (88.52±30.86 ng/g)and total arenic(Tas)(162.32±49.45 ng/g)in blood of GSH group was significantly higher than those(45.32±12.19 ng/g),(108.51±18.00 ng/g),respectively]of arsenic groups(q values were 3.06,6.40,10.72 respectively,P＜0.05).The primary methylated index(PMI)(0.65±0.050)and secondary methyhted index(SMI)(0.55±0.050)in liver sample of GSH group were significantly higher than those(0.58±0.056,0.44±0.093)in arsenic group.In blood samples,the PMI (0.85±0.066)in GSH group was significantly higher than that(0.54±0.113)in arsenic group(q values were 3.75,5.26,4.21 respectively,P＜0.05).However,no significant difference was identified between sodium selenite and arsenic groups in liver,kidney or blood samples.And no significant difference was detected in kidney samples among all arsenic exposing groups.Conclusion Exogenous GSH could promote the methylated metabolism of iAsⅢ,but sodium selenite showed no significant effects.