Adriamycin (doxorubicin), a common cancer chemotherapeutic drug, can be used to induce a model of chronic progressive glomerular disease in rodents. In our studies, we evaluated renal changes in a rat model after Adriamycin injection using two-photon microscopy (TPM), optical coherence tomography (OCT) and Doppler OCT (DOCT). Taking advantage of deep penetration and fast scanning speed for three-dimensional (3D) label-free imaging, OCT/DOCT system was able to reveal glomerular and tubular pathology noninvasively and in real time. By imaging renal pathology following the infusion of°uorophore-labeled dextrans of di®erent molecular weights, TPM can provide direct views of glomerular and tubular°ow dynamics with the onset and progression of renal disease. Speci¯cally, glomerular permeability and¯ltration, proximal and distal tubular°ow dynamics can be revealed. 6-8 weeks after injection of Adriamycin, TPM and OCT/DOCT imaging revealed glomerular sclerosis, compromised°ow across the glomerular wall, tubular atrophy, tubular dilation, and variable intra-tubular°ow dynamics. Our results indicate that TPM and OCT/DOCT provide real-time imaging of renal pathology in vivo that has not been previously available using conventional microscopic procedures. §