Dri chem slide

The mouse blood was allowed to stand for 1 h at room temperature and was then centrifuged at 100× g for 30 min; the supernatant was collected for further analysis. Blood urea nitrogen (BUN) and creatinine levels were measured using a FUJI DRI-CHEM slide (FUJIFILM, Tokyo, Japan) and FUJI DRI-CHEM Analyzer (FUJIFILM).

Serum biochemical levels of BUN and creatinine were measured using FUJIFILM DRI-CHEM NX500 with DRI-CHEM slide (FUJIFILM, Tokyo, Japan) according to the manufacturer’s protocol.

Before imaging, blood samples were collected from all rats under anesthesia. Using a heparinized capillary tube (Marienfeld HSU‐29 00 000, Germany), 0.5–1 mL of blood was drained from the retro‐orbital sinus and stored at room temperature for 30 min to induce coagulation. For diabetic experiments, the BG level was measured on the spot with a glucometer (Accu‐Chek Guide Set, Roche Diabetes Care GmbH, Germany). The sampled blood was microcentrifuged for 10 min at 10 000 g and 4 °C, and the supernatant (serum) was separated and stored in a deep freezer at below −80 °C. The sCr and BUN concentrations were measured from thawed blood serum samples using an automatic biochemical analyzer (DRI‐CHEM NX700, Fujifilm, Japan) with paired biochemical test slides (DRI‐CHEM SLIDE, Fujifilm, Japan).