用~3H-TdR研究混合重金属对鲫鱼DNA合成的影响

应用3 H 胸腺嘧啶核苷 ( 3 H TdR)示踪法研究混合重金属对鲫鱼 (Carassiusaura tus)遗传毒性的影响。结果表明 ,最佳取样时间为注射3 H TdR后 6h。鱼体各组织对混合重金属的毒性反应呈现双向效应 ,即低浓度时 ,表现出损伤、修复作用 ;高浓度时 ,DNA合成受到抑制。鱼卵、鱼鳃对重金属最敏感 ,损伤浓度为 0 0 773mg L ;而大脑对混合重金属耐受性最强。DNA损伤修复作用和DNA合成作用都存在剂量效应 ,随着暴露时间的延长 ,毒性作用增大。鱼体各组织对重金属的毒性反应可由DNA损伤修复变成合成抑制。经过 72h暴露后 ,3 H TdR在肝脏、鱼鳃、鱼卵中掺入量约低于对照的 5 0 %。

STUDY ON THE EFFECTS OF MULTIPLE\|METALS ON Carassius auratus DNA SYNTHESIS BY USING ~3H TdR

The multiple\|metals genetoxicity on Carassius auratus was studied by using 3H TdR tracer method. The results demonstrated that the best sampling time was 6h after injection.The exposure concentration experiment showed that the multiple\|metal's toxicity to Carassius auratus was biphasic, and it would damage the DNA strange at low concentration and inhibit DNA at high concentration. It also showed that the ovum and the gill are more sensitive to multiple\|metals than other tissues, and damage concentration to them was 0 0773mg/L.Among the tissues tested the brain endured the highest concentration of multiple\|metals. There existed dose effect for both DNA repair and synthesis inhibition. The toxicity of multiple\|metal on Carassius auratus increased with exposure time. The response of Carassius auratus to multiple\|metal toxicity changed from DNA repair to DNA synthesis inhibition,the amount of 3H TdR incorporated into DNA were 50% lower than the control in the liver, gill and ovum with 72h exposure.