Proliferation capacity of the renal proximal tubule involves the bulk of differentiated epithelial cells

Am J Physiol Cell Physiol. 2008 Jan;294(1):C22-8. doi: 10.1152/ajpcell.00227.2007. Epub 2007 Oct 3.

Abstract

We investigated the proliferative capacity of renal proximal tubular cells in healthy rats. Previously, we observed that tubular cells originate from differentiated cells. We now found 1) by application of bromo-deoxyuridine (BrdU) for 14 days and costaining for BrdU, and the G(1)-phase marker cyclin D1 that the bulk of cells in the S3 segment of juvenile rats were involved in proliferation; 2) that although the proliferation rate was about 10-fold higher in juvenile rats compared with adult rats, roughly 40% of S3 cells were in G(1) in both groups; 3) that after a strong mitotic stimulus (lead acetate), proliferation was similar in juveniles and adults; 4) that there was a high incidence of cyclin D1-positive cells also in the healthy human kidney; and 5) by labeling dividing cells with BrdU for 2 days before the application of lead acetate and subsequent costaining for BrdU and cell cycle markers, that, although a strong mitotic stimulus does not abolish the period of quiescence following division, it shortens it markedly. Thus the capacity of the proximal tubule to rapidly recruit cells into division relies on a large reserve pool of cells in G(1) and on the shortening of the obligatory period of quiescence that follows division.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Age Factors
  • Aging
  • Animals
  • Bromodeoxyuridine
  • Cell Differentiation* / drug effects
  • Cell Proliferation* / drug effects
  • Cyclin D
  • Cyclin-Dependent Kinase Inhibitor p27 / metabolism
  • Cyclins / metabolism
  • Epithelial Cells / drug effects
  • Epithelial Cells / metabolism
  • Epithelial Cells / physiology*
  • G1 Phase
  • Humans
  • Ki-67 Antigen / metabolism
  • Kidney Tubules, Proximal / drug effects
  • Kidney Tubules, Proximal / metabolism
  • Kidney Tubules, Proximal / physiology*
  • Male
  • Mitogens / pharmacology
  • Organometallic Compounds / pharmacology
  • Rats
  • Rats, Wistar
  • Regeneration* / drug effects
  • Stem Cells / drug effects
  • Stem Cells / metabolism
  • Stem Cells / physiology*
  • Time Factors

Substances

  • Cyclin D
  • Cyclins
  • Ki-67 Antigen
  • Mitogens
  • Organometallic Compounds
  • Cyclin-Dependent Kinase Inhibitor p27
  • Bromodeoxyuridine
  • lead acetate