Figure 8.

Cellular proliferation in the renal papilla after transient renal ischemia. (A_C) For detection of whether cellular proliferation occurs in the renal papilla after transient renal ischemia, 36 hours after the episode, kidneys were harvested and papillae were examined. (A) Control and ischemic papillae of the same animal stained with an antibody against the proliferation cell marker Ki-67 (rhodamine). Only the papillae of the post-ischemic kidney showed significant proliferation. (B and C) Control and ischemic papillae of two different experiments in which rats were given a dose of BrdU 1 hour before euthanasia and sections of papilla were examined for BrdU incorporation as marker of DNA synthesis. Sections of renal papillae are 100 μm in thickness. (B) Papillary sections from the outer or juxtamedullary area (top), middle area (middle), and tip (bottom) from control and ischemic kidneys. As shown, DNA synthesis was only detected in the papilla of the post-ischemic kidney, particularly in the outer papilla, the area next to the medulla. (C) In the kidney subjected to transient ischemia, DNA synthesis in papillary cells was most prominent in the region adjacent to the urinary space of the outer papilla. Scale bars: 50 μm.