title: Vitamin A deficiency in mice enhances the colonic level of purine enzyme activity.
abstract: BACKGROUND
  Vitamin A is an important nutritional factor that regulates normal 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 of inflammatory cells in the colon was determined histologically. Activities of adenosine deaminase, adenylate deaminase, purine nucleoside phosphorylase and myeloperoxidase were determined.
  
  
  RESULTS
  VAD in mice induced a significant increase in the number of mast cells per 100 crypts. There was also an abundance of other connective tissue cells such as plasma cells, lymphocytes and neutrophils around the crypts in the lamina propria. The colonic activity of adenosine deaminase and adenylate deaminase was increased due to VAD, whereas purine nucleoside phosphorylase activity remained unchanged. Immunohistochemical analysis showed an increased expression of adenosine deaminase in VAD mice colon. The increase in myeloperoxidase activity was not statistically significant.
  
  
  CONCLUSIONS
  VAD causes upregulation of purine enzyme, which together with an increased number of inflammatory cells might exacerbate colonic injuries in VAD condition.
authors: Department of Biochemistry, Faculty of Medicine, Health Sciences Center, Kuwait University, Safat, Kuwait.
authors: F M
authors: FM
authors: Al-Awadi
authors: S M
authors: SM
authors: Karam
authors: I
authors: I
authors: Khan
mesh_terms: D000659:AMP Deaminase / Q000378:metabolism; D000243:Adenosine Deaminase / Q000378:metabolism; D000818:Animals; D002452:Cell Count; D003106:Colon / Q000201:enzymology* / Q000473:pathology / Q000648:ultrastructure; D007150:Immunohistochemistry; D008407:Mast Cells / Q000166:cytology; D051379:Mice; D008810:Mice, Inbred C57BL; D008854:Microscopy, Electron; D009195:Peroxidase / Q000378:metabolism; D011683:Purine-Nucleoside Phosphorylase / Q000378:metabolism; D015854:Up-Regulation; D014802:Vitamin A Deficiency / Q000201:enzymology* / Q000473:pathology
chemical_list: D009195:Peroxidase; D011683:Purine-Nucleoside Phosphorylase; D000243:Adenosine Deaminase; D000659:AMP Deaminase