Proliferation of colonic lymphocytes in response to inflammatory cytokines is lower in mice fed fish oil than in mice fed corn oil.

The literature supports an association of chronic inflammation with the development of tumors. The colon contains a specialized lymphocyte population that may influence various stages of colon carcinogenesis. Dietary factors are known to affect both inflammation and tumor development in this tissue. Diets high in n-6 fatty acids are considered to be proinflammatory and tumor-promoting whereas n-3 fatty acids are not. This study examined the proliferative response of colonic lymphocytes (CL) from BALB/c mice fed a diet high in either corn oil or menhaden oil when cultured in the presence of proinflammatory cytokines. CL were isolated from mice fed one of the experimental diets and cultured in the presence of anti-CD2, IL-1beta, IL-2, or TNF-alpha. Proliferation of CL in culture was measured by BrdU incorporation. CL from mice fed the high n-3 diet showed lower rates of proliferation following exposure to the inflammatory cytokines than CL from mice fed the high n-6 diet. CL from the high n-3 group showed the same proliferative potential as those from the n-6 diet group following exposure to a combination of anti-CD2 and TNF. Results from this study indicate that diets high in n-3 fatty acids slow the inflammatory response in the colon as compared to diets high in n-6 fatty acids. The n-3 lipids do not appear to compromise overall immune potential, however.