Abstract: Objective To observe the role of thioredoxin interacting protein (TXNIP) in the proliferation of islet β cells promoted by Glucagon-like peptide 1 (GLP-1). Methods The mice were divided into db/m group and db/db group; TXNIP over-expression (Ad-TXNIP-GFP) MIN6 cells were constructed by stably transfected with lentivirus, which were divided into control group, Ad-GFP group and Ad-TXNIP-GFP group. Western blot was used to detect the expression of TXNIP and proliferating cell nuclear antigen (PCNA) in pancreatic tissues of db/m and db/db mice. The morphology of the islets, the number of β cells, GLP-1R and Ki67 were observed by HE and immunohistochemistry method. The expression of GLP-1 in serum was detected by ELISA. The level of GLP-1R protein in pancreatic tissue was detected by immunohistochemistry. Results Islet structure was destructed, the number of β cells and PCNA expression decreased in pancreatic tissue of db/db mice (P＜0.05). The level of GLP-1 in serum reduced (P＜0.05), and the level of GLP-1 receptor in pancreatic tissue and islet was reduced (P＜0.05). The expression of TXNIP in pancreatic tissues of db/db mice increased (P＜0.05). The TXNIP overexpression cell model was successfully constructed (P＜0.05), and the level of GLP-1 receptor decreased in islet β cells (P＜0.05). The overexpression of TXNIP reduced the proliferative effect of islet β cells to GLP-1 (P＜0.05). Conclusions TXNIP acts on the GLP-1 receptor to reduce the proliferation of islet β cells promoted by GLP-1.

Key words: thioredoxin interacting protein, GLP-1, GLP-1 receptor, cell proliferation