Glucagon-like peptide-1 attenuates liver injury in the rat diabetes model

The aim of present study is to examine the effect of glucagon-like peptide-1(GLP-1) on diabetes-induced liver injury and explore detailed mechanisms of GLP-1 hepatoprotective effect. 150 male Sprague-Dawley rats were randomly assigned into three groups with equal number, including Sham group, diabetes group and GLP-1 intervention group. Diabetes rat model was performed with intraperitoneal injection of streptozotocin (STZ, 65mg/kg). Fasting blood-glucose of rat model was assessed at 72h after STZ injection to verify diabetes rat model. Rats in Sham group were normally fed. Rats in GLP-1 intervention group received 2 ng/kg GLP-1 intervention, at 2, 4, 6 and 8 weeks after intervention, TUNEL staining were performed to examine apoptosis of liver tissue. PCR and Western blot were performed to examine insulin, GLP-1R, autophagy-associated gene and HDAC-1. Compared with diabetes group, insulin expression of GLP-1 intervention group increased significantly (P<0.05). TUNEL staining at different time showed apoptosis levels of liver tissues were reduced gradually after GLP-1 intervention (P<0.05). Compared with diabetes groups, the expressions of BCL2 and GLP-1R were increased, while the levels of caspase3 and LC3 were reduced in GLP-1 intervention group (P<0.05). GLP-1 treatment decreased levels of phosphorylated AKT, phosphorylated ERK1/2, and HDAC6 in liver tissues (P<0.05). GLP-1 treatment alleviated diabetes-induced liver injury via regulating autophagy. The mechanism of GLP-1 hepatoprotective effect could be via GLP-1R-ERK1/2-HDAC6 signaling pathway.