Effects of aging on expression of genes involved in regulation of proliferation and apoptosis in the colonic epithelium

Heung Man Lee, George H. Greeley, Ella W. Englander

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


The purpose of this study was to characterize the effects of aging on colonic messenger ribonucleic acid (mRNA) and protein levels of genes involved in the regulation of cell proliferation and apoptosis, and epithelial morphology in male Fischer 344 rats. Our study shows that, with aging, colonic expression of insulin-like growth factor-1 (IGF-1) and IGF-binding protein-3 (IGFBP-3) is significantly increased and decreased, respectively. Colonic Bax protein levels are increased significantly with aging. Immunohistochemical localization of Bax protein shows a greatly increased expression in colonic crypts, especially in the upper portion of crypts. p53 expression is unchanged with aging. No significant change in proliferation of colonic crypt cells is observed by bromodeoxyuridine (BrdU) labeling, although the increased colonic expression of IGF-1 and the decreased expression of IGFBP-3 with aging may result in an increased colonic IGF-1 bioactivity. The age-related changes in Bax and IGFBP-3 appear to be independent of p53. The finding of an unchanged colonic epithelium with aging in the face of a greatly increased Bax protein levels may suggest that the elevated Bax protein levels function to render colonic epithelial cells more sensitive to apoptotic stimuli. Copyright (C) 2000 Elsevier Science Ireland Ltd.

Original languageEnglish (US)
Pages (from-to)139-155
Number of pages17
JournalMechanisms of Ageing and Development
Issue number3
StatePublished - Jun 20 2000


  • Bax
  • Bcl-2
  • IGF-1
  • IGFBP-3
  • p53

ASJC Scopus subject areas

  • Aging
  • Biochemistry
  • Developmental Biology
  • Developmental Neuroscience


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