镉对大鼠胰脏的毒作用

目的探讨镉对内分泌和外分泌功能的影响。方法将96只SD大鼠分为4组,分别为对照组和50、100、200mg/LCdCl2染毒组,饮水染毒30、60、90d。测定不同染毒时间大鼠血糖、尿糖、血胰岛素、淀粉酶的改变及血液中金属含量的改变;测定尿N-乙酰-β-D-氨基葡萄糖苷酶(NAG);并测定了胰脏组织中金属的含量以及胰脏金属硫蛋白基因、胰岛素基因和淀粉酶基因的表达情况。结果染毒组大鼠血糖水平在染毒90d的中、高剂量组有明显增加,差异有统计学意义(P<0.05),中剂量组血糖平均值为5.83mmol/L,高剂量组为6.46mmol/L;发现尿糖水平的增高先于尿NAG的增高。各剂量组大鼠血液和胰脏中镉的含量明显增加。在染毒90d中、高剂量组血锌含量降低。在染毒30d的中、高剂量组血液中胰岛素水平明显降低,而血淀粉酶改变不明显。在染毒90d的中、高剂量组胰脏组织中锌的含量明显增加。胰脏中金属硫蛋白基因表达均有不同程度的增加;胰岛素基因的表达除染毒60d中剂量组明显降低外,其他各组差异均无统计学意义(P>0.05)。而胰淀粉酶的基因表达在染毒60d和90d的中、高剂量组均明显增高。结论镉可以在胰脏组织蓄积,引起组织中必需元素锌水平的改变,导致基因和蛋白表达的改变,进一步引起胰脏内、外分泌功能的改变。

The toxic effects of cadmium on pancreas

Objective In order to explore the toxic effects of cadmium on functions of endocrine and exocrine of pancreas. Methods 96 SD rats were administered with cadmium at different doses(0,50,100,200 mg/L) by drinking water for 30 days,60 days and 90 days.The contents of cadmium and zinc in the blood and pancreas,also the glucose level in blood and urine,the levels of insulin and the activity of amylase were determined.The gene expression of metallothionein(MT),insulin and pancreatic amylase were also measured. Results The results showed that the contents of cadmium in the serum and pancreas were higher than that of the control groups(P<0.05).The contents of zinc in serum were decreased in the groups of 100 and 200 mg/L cadmium at the 90-day.As well as increased zinc in pancreas.The gene expression of insulin was not different compared with those of the control group except the middle-dose group at the 60-day.And the expression of amylase were higher in the groups of 100 and 200 mg/L cadmium at the 60-day and the 90-day.The expression of MT-1 and-2 were higher in the pancreas after cadmium administration. Conclusion It is suggested that cadmium could be accumulated in the pancreas and caused the change of the zinc levels.Then it resulted in the change of the expression of gene and protein,and influence of the functions of both endocrine and exocrine in pancreas.