Effect of activity-stress on experimental rat colon carcinogenesis: early histopathologic changes and colon tumor induction.
The effect of stress on experimental colon carcinogenesis was investigated in the rat by adapting the activity-stress ulcerogenesis model to the 1,2-dimethylhydrazine (DMH) rat colon carcinogenesis model. Activity-stress was applied intermittently (normal housing conditions alternated with activity-stress conditions on an equal time basis) to DMH-injected rats either throughout the experiment (AS-DMH) or following completion of DMH injections (DMH-AS). The AS-DMH treatment was associated with reduced colonic tumor induction compared with controls, as was to a lesser degree with DMH-AS condition. In a separate study, the early histopathologic effects on the colon of a single DMH injection, an activity-stress treatment, or the combination of both DMH and activity-stress treatments were compared with those of controls. Activity-stress moderated DMH-induced increases in colonic epithelial cell proliferation and nuclear hyperchromia when compared with DMH treatment alone. The findings of activity-stress-associated protection on colon tumor induction and the concordance of these results with quantitative early histopathologic alterations demonstrate that in the rat activity-stress exerts a protective influence in colon carcinogenesis. In addition, these results suggest further that risk modifiers of colon cancer can be assessed in short-term studies that quantify early histopathologic alterations.
Andrianopoulos
G D
GD
Section of G.I. Surgery, University of Illinois Hospital, Chicago 60612.
Nelson
R L
RL
Misumi
A
A
Bombeck
C T
CT
Nyhus
L M
LM
D000818:Animals; D002471:Cell Transformation, Neoplastic / Q000139:chemically induced; D003110:Colonic Neoplasms / Q000139:chemically induced / Q000473:pathology* / Q000648:ultrastructure; D004127:Dimethylhydrazines; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013315:Stress, Psychological / Q000150:complications*
D004127:Dimethylhydrazines