Effects of hyperglycemia on the Pdx-1 gene in fetal rat islets in vitro / 重庆医科大学学报

ABSTRACT

Objective:To investigate the effects of hyperglycemia on the pancreas and duodenal homeobox gene-1 (Pdx-1) and insulin gene in fetal rat islets in vitro.Methods:Fetal rat islets were digested by collagenase and underwent culture at 5.5 mmol/L, 11.1 mmol/L and 33.3 mmol/L glucose concentration respectively.The insulin content of fetal rat islets and insulin releasing test were measured by radioimmunoassay.The expression of Pdx-1 protein and mRNA were evaluated by indirect immunofluorescence cytochemistry staining and reverse transcriptase-polymerase chain reaction (RT-PCR).Results:The results showed that the insulin content and stimulated index of hyperglycemia group 1 ( 11.1 mmol/L) were significantly higher than that of controls ( 5.5 mmol/L) and hyperglycemia group 2 ( 33.3 mmol/L).The majority of Pdx-1 positive cells in control group were confined to the nuclear periphery, but the majority of Pdx-1 positive cells in hyperglycemia groups were translocated to the nucleoplasm, and the expression of Pdx-1 mRNA was also elevated in hyperglycemia groups.However,the expression of insulin mRNA decresed in hyperglycemia group 2.Conclusion:Hyperglycemia may regulate Pdx-1 in fetal rat islets by increasing its protein level and translocation to the nucleus.