On the dynamic variations of metallothionein in the different tissues of Carassius auratus due to the exposure of different concentrations of cadmium

The present article aims to investigate the impact of waterborne cadmium on the content of metallothionein (MT) in different tissues of Carassius auratus under the experimental conditions. To be accurate,the experimental conditions can be stated as follows: the water temperature stands between (16.5±1.0) ℃; the average length of the fish is (15.32±0.63) cm with the middleweight being (310.60±5.69) g. The results of our experiments show that the normal trace value of MT in the different tissues of Carassius auratus proves relatively stable during the experimental period,though its contents in the different tissues were found different,for example,those in the gill,muscle,liver and kidney,respectively. The order of the MT contents in the above said tissues can be stated as follows: liverkidneygillmuscle. Actually,the contents of MT in the gill,liver and kidney are likely to be as high as up to the maximum in 12 hours,and then it would be likely to drop a little and tend to get steady. However,in the muscles,with the prolonging of the exposure time,the contents of MT would rise to its peak value,though the exposure time would not go beyond 12 hours. A positive relation could be found with the increase of the mass concentrations of cadmium in water. That is to day,the more the content of MT in water,the stranger the dose-response. Therefore,the conclusion tends to indicate that cadmium in water can induce the production and expression of MT in tissues of Carassius auratus at the first 12 hours when being exposed,which means that MT in the liver,kidney and gill can be used as a biomarker for evaluation of the pollution of the exogenous heavy metal.