Vitamin A deficiency in mice enhances the colonic level of purine enzyme activity

Background: Vitamin A is an important nutritional factor that regulates nor mal growth and functions of epithelial cells of the gastrointestinal tract. Objective: The objective of this study was to examine the role of vitamin A on the histological and biochemical changes in the colon of mice. Methods :To address this issue, vitamin A deficiency (VAD) was developed in mice by placing them on a VAD diet from weaning up to 120-170 days. Infiltration o f inflammatory cells in the colon was determined histologically, Activities of adenosine deaminase, adenylate deaminase, purine nucleoside phosphoryla se and myeloperoxidase were determined. Results: VAD in mice induced a sign ificant increase in the number of mast cells per 100 crypts. There was also an abundance of other connective tissue cells such as plasma cells, lympho cytes and neutrophils around the crypts in the lamina propria. The colonic activity of adenosine deaminase and adenylate deaminase was increased due t o VAD, whereas purine nucleoside phosphorylase activity remained unchanged. Immunohistochemical analysis showed an increased expression of adenosine d eaminase in VAD mice colon. The increase in myeloperoxidase activity was no t statistically significant. Conclusions: VAD causes upregulation of purine enzyme, which together with an increased number of inflammatory cells migh t exacerbate colonic injuries in VAD condition. Copyright (C) 2000 S. Karge r AG, Basel.