重金属镉锌联合胁迫下鲫鱼组织中金属硫蛋白的动态变化

以鲫鱼(Carassius auratus)为试验材料,研究了重金属镉锌联合胁迫对鲫鱼肝脏和肾脏组织中金属硫蛋白(MT)含量的影响。结果表明,在0.005、0.010、0.050、0.100、0.500 mg.L-1镉分别与1.0 mg.L-1锌联合胁迫下,鲫鱼肝脏和肾脏组织中MT含量的总体变化趋势较为一致,均为先升高后降低再升高,MT含量在第12小时达到峰值,肝脏MT含量达(5.735±0.016)~(10.640±0.023)μg.g-1,肾脏MT含量达(8.346±0.014)~(12.990±0.031)μg.g-1。在试验的0—12 h内肝脏中MT增加速率为0.22~0.69μg.g-1.h-1,在试验的0—6 h内肾脏中MT增加速率为0.83~1.67μg.g-1.h-1。在0—12 h内鲫鱼肝脏和肾脏组织中MT增加量与镉含量呈正相关,表现出一定的剂量-效应关系,表明水体中镉锌联合可诱导鲫鱼组织中MT的合成与表达,且诱导时间主要在0—12 h之内。研究表明,鲫鱼肝和肾组织中MT可作为评价外源重金属污染的指标。

Dynamics of Metallothionein in Organs of Carassius auratus Under Combined Stresses of Cd and Zn

Impact of combined stress of heavy metals, cadmium and zinc in water was studied on content of metallothionein (MT) in liver and kidney of Carassius auratus living therein under a given experimental condition. Results indicate that after exposure to 0.005, 0.010, 0.050, 0.100, 0.500 mg·L~(-1) Cd & 1.0 mg·L~(-1) Zn, the fishes showed a similar trend of MT content in their livers and kidneys, rising-falling-rising, with a peak value appearing at the 12th hour of exposure, and ranging from (5.735±0.016) to (10.640±0.023) μg·g~(-1) in liver and from (8.346±0.014) to (12.990±0.031) μg·g~(-1) in kidney. The fishes were all higher in the groups of Cd~(2+) & Zn~(2+) treatments than in the groups of Cd~(2+) treatments in MT content in the liver and kidney of C.auratus, indicating that the presence of Zn~(2+) enhanced synthesis of MT in C.auratus tissues. The content of MT in liver rose at a rate of 0.22~0.69 μg·g~(-1)·h~(-1) during the first 12 hours and in kidney at a rate of 0.83~1.67 μg·g~(-1)·h~(-1) during the first 6 hours. A positive relation was observed of MT contents in livers of the fish with Cd~(2+) concentration of the waterbody in 12 h, indicating that coexistence of Cd~(2+) & Zn~(2+) may induce synthesis and expression of MT in C.auratus tissue mainly within the first 12 h. The findings of the study reveal that MT content in the liver and kidney of C.auratus can be used as a bio-indictor of extraneous heavy metal pollution.