Effect of dietary phytosterols on cell proliferation and protein kinase C activity in rat colonic mucosa

Nutr Cancer. 1997;27(2):210-5. doi: 10.1080/01635589709514527.

Abstract

The present study investigated the role of phytosterols in colonic cell proliferation and examined the possible role of protein kinase C (PKC) in this process. A total of 18 male Sprague-Dawley rats weighing 240-270 g were fed, for a period of 22 days, one of three experimental diets: a control diet, a diet supplemented with 0.2% cholic acid, or a diet supplemented with 0.2% cholic acid + 2% dietary phytosterols. Two hours before decapitation, animals were injected with 5'-bromo-2'-deoxyuridine (BrdU, 50 mg/kg body wt ip). Cell proliferation in the proximal colon was measured using a monoclonal antibody to BrdU. PKC activity in the proximal colonic mucosa was assayed using a myelin basic protein as a substrate. Cell proliferation was significantly increased by 276% with 0.2% cholic acid feeding compared with controls. The presence of 2% phytosterols in the diet abolished the cholic acid-induced hyperplasia. Cholic acid induced a 31% expansion of the proliferative zone. Only the cytosolic PKC was significantly lower in the phytosterol-fed group. Neither the total PKC nor the particulate PKC demonstrated an effect of phytosterols on enzyme activity. In conclusion, we found that dietary supplementation with 2% phytosterol has a significant protective effect on enhanced cell proliferation and that this effect is not mediated through the PKC system.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Body Weight / drug effects
  • Bromodeoxyuridine / metabolism
  • Cell Division / drug effects*
  • Cholic Acid
  • Cholic Acids / pharmacology
  • Colon / cytology
  • Colon / drug effects*
  • Colon / enzymology
  • Diet*
  • Eating / drug effects
  • Intestinal Mucosa / cytology
  • Intestinal Mucosa / drug effects
  • Intestinal Mucosa / enzymology
  • Male
  • Phytosterols / administration & dosage
  • Phytosterols / pharmacology*
  • Protein Kinase C / metabolism*
  • Rats
  • Rats, Sprague-Dawley

Substances

  • Cholic Acids
  • Phytosterols
  • Protein Kinase C
  • Cholic Acid
  • Bromodeoxyuridine