邻苯二酚氨羧酸螯合剂对放射性钍的促排效果比较

EVALUATION OF THE EFFICACY OF CHELATING AGENT OF CATECHOL AMINO CARBOXYLIC ACID FOR REMOVAL OF RADIOTHORIUM

动物实验观察立即单次及连续给予单、双分子取代邻苯二酚氨羧酸螯合剂 760 1和 95 0 1、95 0 2对2 34 Th中毒大鼠和小鼠的促排作用 ,以大鼠尿、粪中2 34 Th排出量的增高、小鼠整体和肝、骨组织中2 34 Th蓄积量的降低与对照组比较作为评价指标 ,与DTPA相比较。体外实验采用凝胶色谱法测定 760 1和 95 0 1与牛血清白蛋白络合竞争Th的能力及ESR方法测定其清除超氧阴离子自由基 (O- .2 )的作用。结果表明 ,760 1和 95 0 1、95 0 2均有较高的促排效果 ,中毒后立即单次给药使大鼠尿、粪中2 34 Th排出量达 63 %～70 % ,连续 3天给药使小鼠整体2 34 Th蓄积量比中毒组下降 82 %～ 88% ,肝、骨中的蓄积量均明显降低 ,760 1和 95 0 1的促排效果明显优于DTPA。 760 1、95 0 1和DTPA三者促排效果强弱差别和三者与血清蛋白络合竞争钍的能力相一致。 95 0 1和 760 1具有较强的直接清除O- .2 的作用 ,达到BESOD的水平。初步探讨了 760 1和 95 0 1防护核素内照射损伤的作用机制。

The efficacy of prompt single and consecutive administration of chelating agent 7601 and 9501 of catechol amino carboxylic acid for the decorporation of 234Th in rats and mice was investigated. DTPA was used as positive control. The complexing competitive abilities of 7601 and 9501 to mobilize the thorium with bovine serum albumin were studied with gel chromatography in vitro. The inhibition effect of 7601 and 9501 on superoxide anions radicals (O -. 2) were measured with electron spin resonance. The results showed that 7601 and 9501 could increase the excretion of 234Th in urine and feces by 63%～70% and decrease markedly retention of 234Th in liver and skeleton, which have been proved to be superior to DTPA. Their different bioactivities for decorporation of 234Th were consistant with their competitve abilities to mobilize the thorium with bovine serum albumin. 7601 and 9501 could directly scavenge O -. 2. Their effects as an O -. 2 scavenger were very significant and were similar to that of BESOD. The mechanism of protective effects of 7601 and 9501 for internal exposure injury was close related to decorporation effectiveness and the activity of scavenging oxygen free radical.