重金属镉在鲫鱼鳃组织中的积累及其对P-糖蛋白基因表达的影响

Accumulation of Cadmium in the Gill of Carassius auratus and Its Effect on Gene Expression of P-glycoprotein

以鲫鱼(Carassius auratus)为试验材料,研究了在2.12、4.23、8.46 mg/L不同浓度镉(CdCl2·2.5H2O)的胁迫下,Cd在鲫鱼鳃组织96 h内的富集量及其对P-糖蛋白(P-glycoprotein,P-gp)活性和mRNA表达的影响。结果表明,不同Cd浓度和时间处理均对鲫鱼腮内的Cd富集量、P-gp的活性变化及基因表达量有明显影响。暴露于2.12 mg/L Cd后,Cd的富集量在48 h达到最大值,之后有所降低并趋于稳定;暴露于4.23、8.46 mg/L Cd后,Cd的富集量随着处理时间的延长明显升高,呈明显的时间依赖关系。在Cd的胁迫下,鲫鱼鳃组织中P-gp的活性以及mRNA的表达显著升高(P<0.05),且在不同Cd浓度处理下,P-gp活性和mRNA的表达均在72 h达到最大。研究表明P-gp在鲫鱼自身抗Cd机制中发挥了作用,可较敏感地反映水环境中重金属Cd浓度或含量。

Taken Carassius auratus as experimental material,the accumulation of cadmium in gill tissues of Carassius auratus and its effect on P-glycoprotein(P-gp)activity and gene expression at different Cd exposure concentrations(2.12,4.23 and 8.46 mg/L)in 96 h were studied in this paper. The results showed that the different concentrations and time of Cd had significant effects on the accumulation of Cd,the activity of P-gp and gene expression in the gills of Carassius auratus. After exposed to 2.12 mg/L Cd,the accumulation of Cd reached its maximum at 48 h,and then decreased to a stable level. After exposed to 4.23 and 8.46 mg/L Cd,the accumulation of Cd increased significantly with the prolongation of exposure time,showing a significant time-dependent relationship. After Cd treatment,the activity of P-gp and the expression of mRNA in gill tissues of Carassius auratus increased significantly(P<0.05)and reached the maximum at 72 h under different Cd concentrations. These results suggest that P-gp plays an important role in the mechanism of resistance to Cd in Carassius auratus. It can reflect the concentration or content of Cd in water environment sensitively.