Label-free whole-kidney metabolic optical imaging using in vivo insulated cryofixation and cryo-micro-optical sectioning tomography.

Cryo-imaging has the potential to obtain and visualize the metabolic state of the whole kidney without labeling. However, uneven fixation of metabolic information and incomplete organ morphology in three dimensions limit cryo-imaging application. Here, a pipeline of in vivo insulated cryofixation combined with cryo-micro optical sectioning tomography (cryo-MOST) was established to achieve uniform and complete cryofixation and three-dimensional visualization of renal metabolic mapping at a micron-scale resolution. By this pipeline, we discovered an increased renal redox ratio of db/db mice with type 2 diabetes, indicating the presence of metabolic disorders. The results demonstrate that our convenient optical imaging tool provides a micro-resolution, quantitative assessment of the metabolic state of the whole kidney and potentially extends to other organs.