Bioluminescence Imaging in Mouse Models Quantifies β Cell Mass in the Pancreas and After Islet Transplantation

We developed a mouse model that enables non-invasive assessment of changes in beta cell mass. We generated a transgenic mouse expressing luciferase under control of the mouse insulin I promoter [mouse insulin promoter-luciferase-Vanderbilt University (MIP-Luc-VU)] and characterized this model in mice with increased or decreased beta cell mass and after islet transplantation. Streptozotocin-induced, diabetic MIP-Luc-VU mice had a progressive decline in bioluminescence that correlated with a decrease in beta cell mass. MIP-Luc-VU animals fed a high-fat diet displayed a progressive increase in bioluminescence that reflected an increase in beta cell mass. MIP-Luc-VU islets transplanted beneath the renal capsule or into the liver emitted bioluminescence proportional to the number of islets transplanted and could be imaged for more than a year. Bioluminescence in the MIP-Luc-VU mouse model is proportional to beta cell mass in the setting of increased and decreased beta cell mass and after transplantation.