Figure 2.

Intravital microscopy studies of the Indiana O’Brien Center. A: proximal tubule endocytosis of filtered Alexa 568-albumin in the rat. Multiphoton fluorescence image of the kidney of a living rat after intravenous injection of Hoechst 33342 (blue nuclei) before (A) and 24 min after (B) intravenous injection of Alexa 568-albumin. Alexa 568-albumin can be seen in the glomerular and intertubular capillaries and in endosomes of proximal tubule cells. Scale bar = 30 µm. [Figure adapted from Russo et al. (6).] C and D: oxidative stress in S2 segments of the mouse proximal tubule 2 h after intravenous injection of bacterial endotoxin. Endotoxin (red) binds to S1 segments, but oxidative stress can be observed in downstream S2 segments (green, 2′,7′-dichlorofluorescin diacetate). Scale bar = 40 µm in length. [Figure adapted from Hato et al. (11).] E: colonization of the rat proximal tubule by Escherichia coli following tubular microperfusion. At time 0, green fluorescent protein-expressing bacteria were injected into the lumens of tubules outlined with blue dextran. A fraction of the injected bacteria bound to the tubules, subsequently increasing in number and inducing tubular and endothelial injury. Scale bar = 30 µm in length. [Figure adapted from Melican et al. (32).] G, glomerulus; H₂DCFDA, 2′,7′-dichlorodihydrofluorescein diacetate; LPS, lipopolysaccharide; PT, proximal tubule.