| OBJECTIVE: To investigate the effects of free fatty acid(FFA)on cell apoptosis in murine MIN6 pancreaticβ-cells and the changes in signaling pathway of Akt /Bcl-2 in this process.Further, to explore the effect and possible mechanism of Exendin-4 onβ-cells apoptosis induced by FFA.METHODS: Murine MIN6 pancreaticβ-cells were cultured in vitro and the cell apoptosis model of lipotoxicity was established by FFA. Cells were pretreated with Exendin-4 at the concentration of 12.5 to 200nmol/L.Choose a correct concentration of Exendin-4 to continue the following study.Cell viability was measured by MTT assay.The morphological changes of cell damage was evaluated by epifluorescence microscopy after staining with Hoechst-PI.The percentage of cell apoptosis was determined by flow cytometric assay after Annexin-Ⅴ-FITC-PI staining. Protein levels of Akt,P-Akt,Bcl-2 and Bax were detected by Western blot.RESULTS: MIN6 cells viability were significantly reduced in a dose-dependent manner after exposure of MIN6 cells to free fatty acid at range of 0.4-1.6 mmol/L for 24 and 48 hours.It was verified by Hoechst-PI and Annexin-Ⅴ-FITC-PI staining that the percentage of cell apoptosis was significantly increased after treating with FFA. Meanwhile,the protein levels of P-Akt,Bcl-2 but Akt,Bax were dose-dependently decreased.Intriguingly, cell apoptosis was dose-dependently reduced by being pretreated 24 hours with Exendin-4.Furthermore,the present study showed that Exendin-4 patently inhibited the decreased protein levels of P-Akt,Bcl-2 induced by FFA.CONCLUSION: The cell signaling pathway of Akt/ Bcl-2 mediated FFA-induced apoptosis in MIN6 pancreaticβ-cells. Exendin-4 protectedβ-cells from FFA-induced apoptosis via up-regulation of Akt/ Bcl-2 pathway.Glucagon-like peptide-1 receptor agonist—Exendin-4 is potentially a highly effective therapeutic agent in protecting pancreaticβ-cells.
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