亚硒酸钠与硒代蛋氨酸对镉在大鼠体内分布的影响

Effects of Sodium Selenite and Selenomethionine on the Distribution of Cadmium in Cadmium - Induced Poisoning Rats

目的 比较亚硒酸钠(Na_2SeO_3)与硒代蛋氨酸(SeMet)对镉(Cd)毒性的拮抗效应,探讨体内Cd的代谢分布在硒(Se)拮抗Cd毒性作用中的意义。方法 健康雄性Wistar大鼠36只,随机分为6组。Ⅰ组为正常对照组,Ⅱ组为Cd中毒组,Ⅲ组为Na_2SeO_3组,Ⅳ组为SeMet组。Ⅴ组为Cd+Na_2SeO_3组,Ⅵ组为Cd+SeMet组。Cd按100μmol·kg^(-1)体重,Se按10μmol·kg^(-1)体重的剂量隔日1次经口灌胃,其中Ⅴ组和Ⅵ组按先Se后Cd交替灌胃。Se、Cd均灌胃15次。实验时间为30d。实验结束后,取全血、肝脏、肾脏、睾丸,测定其Se、Cd含量。结果 Cd在体内的蓄积主要分布于肝脏和肾脏,全血和睾丸含量较少,Cd的组织分布顺序为肝脏>肾脏>睾丸>全血。2个Cd加Se保护组组织中Cd含量没有减少,表明Se不能促进Cd的排泄。Cd+Na_2SeO_3组肝脏Cd含量明显高于单独给Cd组,但Se含量并未相应增加;Cd+SeMet组大鼠组织Cd含量与单独给Cd组比没有明显差异,由此不能证实有Se-Cd复合物的形成。各组织Se含量,SeMet组明显高于Na_2SeO_3组,表明其生物利用度与Se化合物的形式有关。2种Se化合物吸收后其组织Se的分布顺序均为:全血>肾脏>肝脏>睾丸。结论 Cd在大鼠体内的分布具有脏器选择性,Na_2SeO_3和SeMet对Cd体内分布的影响具有一定的差异,但均不能促进Cd的排泄。

Objective To compare the efiects of sodium selenite .(Na2SeO3) and selenomethionine (SeMet) on cadmium toxicokinetics, and to assess the protective effects of both selenium compounds on cadmium - induced poisoning rats. Methods 36 adult male Wistar rats were allotted at random to 6 groups of 6 each. Rats were given selenium as Na2SeO3 or SeMet (10 μmol· kg-1) and cadmium as cadmium chloride (100 μmol· kg-1) every other day by oral route of administration.The 6 groups of rats were used as follow, Group I : control, group II : Cd, group III : Na2SeO3, group IV: SeMet, group V : Cd+Na2SeO3, and group VI: Cd + SeMet. After 30 days, blood, liver, kidneys and testes were sampled.The selenium and cadmium concentrations of all samples were determined by the methods of fluorospectrophotometry and atomic absorption spectrometry, respectively. Results Over 30d period the cadmium content was the highest in the liver, followed in descending order by the kidneys, testes and blood.The cadmium content in selenium treated rats was not decreased, suggesting that Na2SeO3 and SeMet fail to increase the excretion of cadmium. Liver cadmium accumulation was increased markedly by sodium selentie treatments, while the levels of cadmium in liver remained unaltered by SeMet. With cadmium levels increase in liver, selenium levels did not increase simultaneously, which suggests that oral administration of selenium fail to form complexes with cadmium.Selenium content in all samples from treated rats was higher than those from Na2SeO3 treated rats, suggesting that Na2SeO3 and SeMet have differential metabolism in rats. Conclusion Na2SeO3 and SeMet show different effects on cadmium toxicokinetics, both of which did not increase the excretion of cadmium and did not form complexes with cadmium.