Transplacental effects of maternal feeding with high fat diets on lipid exchange and response of the splenic lymphoid system in mice offspring exposed to low doses of carcinogen

We studied whether feeding pregnant female mice with different fats affects lipid exchange and activity of the splenic lymphoid system in offspring ex posed to low doses of carcinogen. Female mice were fed diets with either 7% or 15% corn oil or olive oil. The 4-week-old offspring of these mice were transferred to a chow diet, and exposed to a low dose of the carcinogen, di methylbenz(a)antracene (2 mg/kg). Results of experiments were studied 5 mon ths later. Concentrations of polyunsaturated linoleic and oleic acids were determined in the blood and liver of mothers and offspring. The activity of the splenic immune system in offspring was studied using immunohistochemic al methods for evaluating the number of different types of lymphocytes (B a nd T cells), mitotic and apoptotic indexes and the number of Fas-positive l ymphocytes. Serum concentrations of the fatty acids examined were unchanged in the blood of the mothers and their offspring. Concentration of both lin oleic and oleic acids was significantly higher in the liver of mothers fed the 15% olive-oil or corn-oil diets. This high level was maintained in lino leic acid in offspring of mothers fed the 15% olive-oil diet. Spleen weight was higher in offspring of mothers fed a 15% corn-oil diet compared to tho se fed the 7% corn-oil diet. The 15% olive-oil diet slightly decreased the weight of the spleen compared to counterparts fed the 15% corn-oil diet. Im munohistochemial studies showed that the olive diet, partially of 15%, sign ificantly stimulated B-cell blast transformation. The finding reflects the reaction of B lymphocyte-producing splenic zones to the carcinogenic effect , though to a weak extent. T lymphocyte-producing zones did not respond to the diets studied, probably due to the weak carcinogenic effect and lack of tumor appearance. The Fas activity of both B and T cells in the spleen was stimulated by the carcinogen and enhanced by feeding the mothers on the ol ive-oil diet. Maternal feeding with a diet rich in olive oil before pregnan cy results in stimulation of morphological and functional attributes of the splenic immune system of the offspring, particularly related to producing of B lymphocytes.