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dc.contributor.advisorLupton, Joanne R.
dc.creatorSanders, Lisa Merle
dc.date.accessioned2006-08-16T19:02:31Z
dc.date.available2006-08-16T19:02:31Z
dc.date.created2005-05
dc.date.issued2006-08-16
dc.identifier.urihttp://hdl.handle.net/1969.1/3764
dc.description.abstractColon cancer is one of the most commonly diagnosed cancers in the US, yet small intestine cancer is a rare event. While there are many similarities between these two tissues, inherent differences such as redox status, may contribute to the variation in cancer occurrence. We examined the difference in reactive oxygen species (ROS) generation, antioxidant enzyme activity and oxidative DNA damage in the small and large intestine of rats under normal conditions and following exposure to exogenous oxidative stress. Basal ROS and antioxidant enzyme activities were greater in the colon than the small intestine, and the balance of ROS to antioxidant enzymes in the colon was more pro-oxidant than in the small intestine. During oxidative stress, ROS and oxidative DNA damage were greater in the colon than the small intestine. Thus the colon responds to oxidative stress less effectively than the small intestine, possibly contributing to increased cancer incidence at this site. We next wanted to understand how diets containing a combination of fish or corn oil and pectin or cellulose may alter the redox environment of the colon. ROS, oxidative DNA damage, antioxidant enzyme activity and apoptosis were measured in colonocytes of rats fed one of four diets containing either corn oil or fish oil and cellulose or pectin. Measurements were madein rats untreated with carcinogen and rats exposed to a chemical carcinogen and radiation. In rats not treated with a carcinogen, fish oil enhanced ROS, and fish oil/pectin suppressed antioxidant enzymes as compared to corn oil/cellulose. Oxidative DNA damage was inversely related to ROS in the fish oil/pectin diet and apoptosis was enhanced relative to other diets. In carcinogen treated and irradiated rats, a similar protective effect was seen with fish oil/pectin as evidenced by a reduction in oxidative DNA damage and enhancement of apoptosis. This suggests that a diet containing fish oil/pectin may protect against colon carcinogenesis by modulation of the redox environment to promote apoptosis and minimize oxidative DNA damage.en
dc.format.extent680318 bytesen
dc.format.mediumelectronicen
dc.format.mimetypeapplication/pdf
dc.language.isoen_US
dc.publisherTexas A&M University
dc.subjectcolon canceren
dc.subjectapoptosisen
dc.subjectreactive oxygen speciesen
dc.subjectantioxidantsen
dc.subjectoxidative stressen
dc.subjectglutathioneen
dc.subjectoxidative damageen
dc.subjectradiationen
dc.subjectanimal modelen
dc.subjectsmall intestineen
dc.subjectfish oilen
dc.subjectomega 3 fatty acidsen
dc.subjectdietary fiberen
dc.titleEffects of dietary fat and fiber on the oxidative status of the small intestine and colon of ratsen
dc.typeBooken
dc.typeThesisen
thesis.degree.departmentAnimal Scienceen
thesis.degree.disciplineNutritionen
thesis.degree.grantorTexas A&M Universityen
thesis.degree.nameDoctor of Philosophyen
thesis.degree.levelDoctoralen
dc.contributor.committeeMemberBurghardt, Robert C.
dc.contributor.committeeMemberCarroll, Raymond J.
dc.contributor.committeeMemberChapkin, Robert S.
dc.contributor.committeeMemberTurner, Nancy D.
dc.type.genreElectronic Dissertationen
dc.type.materialtexten
dc.format.digitalOriginborn digitalen


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