Dietary modulation of Kupffer cell and splenocyte function during a Salmonella typhimurium challenge in mice

Oils from cold-water fish are rich in (n-3) polyunsaturated fatty acids, in particular eicosapentaenoic acid (20:5) and docosahexaenoic acid (22:6). Although those fatty acids are beneficial in the prevention of cardiac disease and have anti-inflammatory properties, they can also decrease survival rates of mice during challenges with food-borne pathogens. This study was designed to determine dietary fat effects on Kupffer cells and splenocytes during a Salmonella typhimurium challenge. Mice were fed a low corn oil diet (3%, control), high corn oil diet (20%, HCO), or a menhaden fish oil diet (17% + 3% corn oil, FO) for 28 days and then orally given 3.1 x 10(8) colony-forming units of S. typhimurium. Kupffer cells and splenocytes were separated immediately prior to and on days 6, 10, and 14 postchallenge. Fish oil decreased Kupffer cell phagocytosis and oxidative burst early in the infection and adhesion molecule (CD18) expression at the end of the infection. In splenocytes, fish oil affected Ia expression prior to and late in the infection and depressed CD18 expression late in the infection. These data suggest that the diet affected Kupffer cells most early in the infection but affected splenocytes primarily later in the infection. Therefore, because the greatest death rate during an S. typhimurium infection occurs early, the reduced function of the Kupffer cells is probably a major factor.