Effects of free fatty acids on the PDX-1 expression and insulin secretion of βTc6 cells

Objective To investigate the changes of pancreatic-duodenal homeobox-1 (PDX-1) expression,and the proliferation and insulin secretion induced by free fatty acid ( FFA) in β cells. Methods Insulinoma cell line βTc6 cells were treated with 0.25-1.00 mmoL/L FFA for 24-48 hours,then the transcription of PDX-1 mRNA,the βTc6 cells' proliferation and the glucose stimulated insulin secretion(GSIS) were determined by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR),MTT viability assay and radioimmunoassay respectively.In addition.the morphological change of βTc6 cells was observed.Results The expression of PDX-1 mRNA was increased gradually after intervention with 0.25-1.00 mmoL/L FFA for 24 hours,but it was decreased when the intervening duration Was prolonged to 48 hours,espectially with 1.00 mmol/L FFA.After treating with 0.50-1.00 mmol/L FFA for 24-48 hours,the βTc6 cells tended to be apoptosis in morphology,and the corresponding proliferation and GSIS also decreased gradually.But the βTc6 cells treating with 0.25 mmol/L FFA for 24 hours didn't appear aforesaid similar changes.Conclusion Abnormal FFA intervention is toxic for islet β cells.FFA with lower concentration will up-regulate the expression of PDX-1,and do not affect β cells' proliferation and insulin secretion in a short time.But the expression of PDX-1 mRNA will be downregulated and β cells' proliferation and insulin secretion will be imDaired with the increase of intervention concentration and duration of FFA. Key words: Free fatty acid; βTc6 cell; Pancreatic-duodenal homeobox-1; Insulin