An increase in reactive oxygen species by dietary fish oil coupled with the attenuation of antioxidant defenses by dietary pectin enhances rat colonocyte apoptosis.
We showed previously that the dietary combination of fish oil, rich in (n-3) fatty acids, and the fermentable fiber pectin enhances colonocyte apoptosis in a rat model of experimentally induced colon cancer. In this study, we propose that the mechanism by which this dietary combination heightens apoptosis is via modulation of the colonocyte redox environment. Male Sprague-Dawley rats (n = 60) were fed 1 of 2 fats (corn oil or fish oil) and 1 of 2 fibers (cellulose or pectin) for 2 wk before determination of reactive oxygen species (ROS), oxidative DNA damage, antioxidant enzyme activity [superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx)] and apoptosis in isolated colonocytes. Fish oil enhanced ROS, whereas the combination of fish oil and pectin suppressed SOD and CAT and enhanced the SOD/CAT ratio compared with a corn oil and cellulose diet. Despite this modulation to a seemingly prooxidant environment, oxidative DNA damage was inversely related to ROS in the fish oil and pectin diet, and apoptosis was enhanced relative to other diets. Furthermore, apoptosis increased exponentially as ROS increased. These results suggest that the enhancement of apoptosis associated with fish oil and pectin feeding may be due to a modulation of the redox environment that promotes ROS-mediated apoptosis.
Sanders
Lisa M
LM
Faculty of Nutrition, Texas A&M University, College Station, TX 77843, USA.
Henderson
Cara E
CE
Hong
Mee Young
MY
Barhoumi
Rola
R
Burghardt
Robert C
RC
Wang
Naisyin
N
Spinka
Christine M
CM
Carroll
Raymond J
RJ
Turner
Nancy D
ND
Chapkin
Robert S
RS
Lupton
Joanne R
JR
D000818:Animals; D000975:Antioxidants / Q000502:physiology*; D017209:Apoptosis / Q000187:drug effects*; D002374:Catalase / Q000378:metabolism; D003106:Colon / Q000166:cytology* / Q000187:drug effects; D004249:DNA Damage / Q000187:drug effects; D004032:Diet; D005395:Fish Oils / Q000008:administration & dosage / Q000494:pharmacology*; D007413:Intestinal Mucosa / Q000166:cytology* / Q000187:drug effects; D008297:Male; D010368:Pectins / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000378:metabolism
D000975:Antioxidants; D005395:Fish Oils; D017382:Reactive Oxygen Species; D010368:Pectins; D002374:Catalase; D013482:Superoxide Dismutase