Dietary fatty acids modulate chronic colitis, colitis-associated colon neoplasia and COX-2 expression in IL-10 knockout mice.
OBJECTIVE
The effects of different dietary oils on the development of colitis-associated colon cancer have not been studied. The present study examined the effect of different dietary oils on the severity of chronic colitis, development of colitis-associated premalignant changes, and colonic expression of cyclooxygenase-2 (COX-2) in interleukin-10 knockout (IL-10-/-) mice.


METHODS
IL-10-/- mice were fed chow supplemented with corn oil (CO; control, n=28), olive oil (OO; n=29), or fish oil (FO; n=35) for 12 wk and their colons were studied for colitis score, premalignant changes, and COX-2 expression.


RESULTS
The average colitis score was higher in the FO than in the CO group. Similarly, the incidence of severe colitis (score>or=3) was significantly higher in the FO than in the CO and OO groups (50% versus 7.7% and 3.7%, respectively, P<0.05). Dysplasia was more frequent in the FO and less frequent in the OO than in the CO group (47% and 4% versus 15%, respectively, P<0.05). Conversely, aberrant crypt foci and crypt index were significantly higher in the FO than in the CO group. Colitis score, aberrant crypt foci, and crypt index did not differ between the OO and CO groups. COX-2 immunostaining was significantly lower in the OO than in CO group (P<0.05) but not different between the FO and CO groups.


CONCLUSIONS
In IL-10-/- mice, fish oil exacerbates chronic colitis and colitis-associated premalignant changes. Conversely, olive oil inhibits COX-2 immunostaining and decreases the risk of neoplasia associated with chronic colitis.
Hegazi
Refaat A F
RA
Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
Saad
Reda S
RS
Mady
Hussam
H
Matarese
Laura E
LE
O'Keefe
Stephen
S
Kandil
Hossam M
HM
D000818:Animals; D003092:Colitis / Q000453:epidemiology / Q000378:metabolism* / Q000473:pathology; D003110:Colonic Neoplasms / Q000453:epidemiology / Q000378:metabolism* / Q000473:pathology; D003314:Corn Oil; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D004042:Dietary Fats, Unsaturated / Q000008:administration & dosage*; D005395:Fish Oils / Q000009:adverse effects*; D007150:Immunohistochemistry; D016753:Interleukin-10 / Q000172:deficiency; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D000069463:Olive Oil; D010938:Plant Oils; D011897:Random Allocation; D012720:Severity of Illness Index
D004042:Dietary Fats, Unsaturated; D005395:Fish Oils; D000069463:Olive Oil; D010938:Plant Oils; D016753:Interleukin-10; D003314:Corn Oil; D051546:Cyclooxygenase 2