Changes of Wnt/ß-catenin signalling, BMP2, and BMP4 in the jejunum during ageing in rats.

BACKGROUND AND STUDY AIMS: The renewal of intestinal epithelium is maintained by intestinal stem cells (ISCs). Studies have found an age-dependent increase of Esg+/Dl+ progenitor cells in the midgut of Drosophila. However, changes of ISCs and the molecular regulation in mammalian animals with age are yet unknown. The aim of this study was to find out the changes of ISCs and molecular regulation in mammalian animals during the process of ageing. MATERIAL AND METHODS: Thirty Sprague-Dawley rats were divided into three groups: young (3 months old), adult (6 months old), and ageing (24 months old). Levels of PCNA, Bmi1, ß-catenin and BMP4 were examined by Immunohistochemistry staining. Levels of Bmi1, GSK-3ß, Dkk1 and BMP2 were determined by Western Blot. RESULTS: Our results showed that the proliferation of ISCs was decreased and the number of intestinal stem cells declined in ageing rats. The niches of ISCs, including Wnt signalling pathway and some proteins of Bone morphogenetic protein (BMP) signalling pathway, were downregulated in the jejunum of ageing rats. CONCLUSION: Our study indicated that age-related decreased proliferation of intestinal stem cells in the jejunum could be associated with the alleviation of niches, including Wnt signalling pathway and some proteins of BMP signalling pathway.