Effect of dietary chlorogenic acid on multiple immune functions and formation of aberrant crypt foci in rats

Adult male Sprague-Dawley rats were fed 70 mg/kg body weight chlorogenic acid (CHA) for 7 wk. One CHA-fed group was also given 2 injections of the colon carcinogen azoxymethane (AZO) on d 2 and 9 of CHA treatment. Three major types of immune responses were assessed: antibody production, specific cell-mediated immunity, and nonspecific cell-mediated immunity. The formation of AZO-induced aberrant crypt foci (ACF) in the colon were observed, as was colonic cell proliferation. There were no significant effects of CHA treatment on any of the immune parameters examined or on formation of preneoplastic lesions or cell proliferation in the colon. The overall nonsignificant trends in immune function, colon cell proliferation, and ACF development were, however, more consistent with immunosuppression and enhanced preneoplasia.