Abstract
Apoptosis is the main form of β-cell death in type 2 diabetes mellitus. There are
2 major pathways leading to apoptosis, ‘intrinsic and extrinsic pathways’. Adiponectin
is an adipocyte-derived hormone, which plays an important role in glucose and lipid
metabolism. The main aims of this study were to investigate related apoptotic pathways
in diabetes and the anti-apoptosis effects of adiponectin on pancreatic β-cell and
the underlying mechanisms. Diabetic mice were generated by intraperitoneal injection
of streptozotocin (STZ, 50 mg/kg/d for 5 days) and high-fat diet. Adiponectin overexpressing
mice were developed by injecting lentivirus expressing mouse full length adiponectin
(plenti-acdc-EGFP) through tail vein. Fourteen days after plenti-acdc-EGFP lentivirus
injection, plasma adiponectin protein levels were increased 2-fold. Plasma triglyceride
and glucose levels, but not total cholesterol, were significantly reduced in plenti-acdc-EGFP-treated
mice. Pancreatic β-cell apoptotic numbers and the expression of caspase-8, -9, -3
in islet increased in diabetic mice, which was reversed by elevated adiponectin in
plenti-acdc-EGFP-treated mice. These results suggest that both intrinsic and extrinsic
apoptotic pathways have an important role in diabetic β-cell apoptosis. Adiponectin
has antidiabetic and anti-apoptotic effects by regulating glucose and lipid metabolisms
and inhibiting intrinsic and extrinsic apoptotic pathway in pancreatic β-cells.
Key words
adiponectin - lentivirus - diabetes - apoptosis - caspase