OBJECTIVE: To investigate the effects of glucagon-like peptide-1 (GLP-1) on high glucose-induced apoptosis of human umbilical vein endothelial cells (HUVECs) and the mechanism involved. METHODS: HUVECs were cultured under varying conditions for 48 h, and the cell viability was spectrophotometrically measured by MTT assay. Flow cytometry detected the ratio of cell apoptosis. Western blot detected the protein levels of p-Akt and p-eNOS, while NO assay kit detected the NO concentration. RESULTS: Treatment of high glucose (33 mmol/L) for 48 h significantly decreased the HUVECs viability and induced the apoptosis of HUVECs, concomitant with decreased Akt and eNOS phosphorylation leves and subsequent NO production. Treatment with GLP-1 (3 nmol/L) for 48 h in the high glucose group increased the HUVECs viability (P<0.01), decreased the ratio of HUVECs early apoptosis (P<0.05), ameliorated the reduced protein levels of p-Akt and p-eNOS caused by high glucose, and increased the NO production (P<0.05). The anti-apoptotic effect and the increased NO production of GLP-1were inhibited by PI3K inhibitor wortmannine (100 nmol/L) or eNOS inhibitor L-NAME (100 μmol/L). The effect on p-Akt, p-eNOS of GLP-1 was inhibited by wortmannine (100 nmol/L) while L-NAME (100 μmol/L) did not have any influence on the expression of p-Akt. CONCLUSION: GLP-1 can ameliorate high glucose-induced HUVECs apoptosis, which is probably related to the up-regulation of PI3K/Akt/eNOS pathway.
OBJECTIVE: To investigate the effects of glucagon-like peptide-1 (GLP-1) on high glucose-induced apoptosis of human umbilical vein endothelial cells (HUVECs) and the mechanism involved. METHODS: HUVECs were cultured under varying conditions for 48 h, and the cell viability was spectrophotometrically measured by MTT assay. Flow cytometry detected the ratio of cell apoptosis. Western blot detected the protein levels of p-Akt and p-eNOS, while NO assay kit detected the NO concentration. RESULTS: Treatment of high glucose (33 mmol/L) for 48 h significantly decreased the HUVECs viability and induced the apoptosis of HUVECs, concomitant with decreased Akt and eNOS phosphorylation leves and subsequent NO production. Treatment with GLP-1 (3 nmol/L) for 48 h in the high glucose group increased the HUVECs viability (P<0.01), decreased the ratio of HUVECs early apoptosis (P<0.05), ameliorated the reduced protein levels of p-Akt and p-eNOS caused by high glucose, and increased the NO production (P<0.05). The anti-apoptotic effect and the increased NO production of GLP-1were inhibited by PI3K inhibitor wortmannine (100 nmol/L) or eNOS inhibitor L-NAME (100 μmol/L). The effect on p-Akt, p-eNOS of GLP-1 was inhibited by wortmannine (100 nmol/L) while L-NAME (100 μmol/L) did not have any influence on the expression of p-Akt. CONCLUSION:GLP-1 can ameliorate high glucose-induced HUVECs apoptosis, which is probably related to the up-regulation of PI3K/Akt/eNOS pathway.