Liraglutide Inhibits High Glucose⁃induced Injury of Mouse Islet Cells / 中国生物化学与分子生物学报

ABSTRACT

Liraglutide is an analog of glucagon⁃like peptide⁃1 and plays an important role in the treatment of diabetes. But the specific mechanism of liraglutide in improving the function of pancreatic β cells is still unclear. Therefore, high glucose (33 mmol/ L) was used to induce islet MIN6 cells for 48 hours to establish a high glucose injury model in this study. The CCK⁃8 assay was used to detect cell viability, and the results showed that the viability of MIN6 cells in the high glucose group decreased (P<0. 05) compared with the control group, and the cell viability increased after liraglutide treatment (P<0. 05). Using the mouse insulin detection kit and ATP content detection kit, we found that both the insulin re⁃ lease (P<0. 01) and ATP content decreased (P<0. 001) in the high glucose group compared with the control group, and after liraglutide treatment both insulin release (P < 0. 05) and ATP content (P < 0. 001) increased. We used the mitochondrial membrane channel pore (MPTP) fluorescence detection kit in MIN6 cells and found that the green fluorescence intensity of the high glucose group was significant⁃ ly decreased (P<0. 001) compared with the control group, and after liraglutide treatment the green fluo⁃ rescence intensity was significantly increased (P<0. 001). The DCFH⁃DA probe combined with flow cy⁃ tometry was used to detect the level of reactive oxygen species (ROS). We found that compared with the control group, the ROS level in the high glucose group was significantly increased (P<0. 001), and de⁃ creased by liraglutide treatment (P<0. 01). Intracellular malondialdehyde (MDA) contents, superoxide dismutase (SOD) and catalase (CAT), and lactate dehydrogenase (LDH) activities in the cell superna⁃ tant were measured, and the levels of MDA and LDH were significantly increased (P<0. 05), and the levels of SOD and CAT were significantly decreased (P<0. 01) in the high glucose group compared with the control group. After liraglutide treatment, the levels of MDA and LDH were decreased (P<0. 05), and the levels of SOD and CAT were increased (P<0. 05). The results of Western blotting showed that the expression of UCP2 was upregulated in the high glucose group (P<0. 01) compared with the control group, and after liraglutide treatment the expression of UCP2 decreased (P<0. 05). The results indica⁃ ted that liraglutide has significant effects in high⁃glucose induced mitochondrial damage, oxidative stress and insulin secretion in MIN6 cells, which will provide a theoretical basis for clinical utilization of liraglu⁃ tide.