金属硫蛋白对奶牛抗氧化酶GSH-Px和CAT基因表达的影响

In order to approach the effects of exogenous metalloehionein on antioxidation regulatory mechanism and antioxidant enzyme gene expression in dairy cattle,an expriment was conducted with 24 lactaing cows from Chinese Holstein, which were randomly divided into four groups A, B, C and D, and supplemented with 0, 4.0, 8.0 and 12.0 mg Zn-MT respectively by intravenous injection. The blood samples were collected every 15 days and the levels of GSH-Px and CAT gene expression in the cows were also determined. The results showed that the GSH-Px gene expression levels of the cows in groups C and D were higher (P<0.05) than those in group A,the CAT gene expression level of the cows in group C was also higher (P<0.05) than those in group A,and the CAT gene expression level of the cows in group D was higher than those in groups A (P<0.01), B(P<0.05) and C (P>0.05) respectively,while there were no significant differences (P>0.05) in both GSH-Px and CAT gene expression levels of the cows between groups A and B. A trend of GSH-Px and CAT gene expression levels which reached the peak at the 30th day and descended at the 45th day after supplying exogenous metallothionein was observed.The GSH-Px gene expression levels of the cows at the 30th day and the CAT gene expression levels at the 15th day and the 30th day after supplying exogenous metallothionein were higher (P<0.05) than those before supplying exogenous metallothionein. All of these suggested that exogenous Zn-MT can impact the GSH-Px and CAT gene expression levels of dairy cattle, and presented time-dependent effects and dose-dependent effects.