Transplacental effect of a 15% olive-oil diet on functional activity of immune components in the spleen and colon tumors of rat offspring

We studied whether feeding pregnant female rats a 15% olive-oil diet affect s the activity of lymph cells in the spleen and tumors in offspring with ch emically-induced colon tumors. Rat mothers were fed either a 7% corn-oil or a 15% olive-oil diet. Five-week-old male offspring were divided into 3 gro ups. A control group was fed the 7% corn-oil diet similar to their mothers. The experimental group I was fed the 7% corn-oil diet whereas their mother s were fed the 15% olive-oil diet. The experimental group II was fed the sa me 15% olive-oil diet as their mothers. Experimental rats were injected wee kly for 8 weeks with the carcinogen, 1,2-dimethylhydrazine (DMH), 20 mg/kg b.w. Results of experiments were studied 6 months later. The area of zones in the spleen responsible for producing B and T lymphocytes were measured a nd the number of cells counted. The activity of lymphoid elements of the sp leen and of tumors were studied using immunohistochemical methods for evalu ating the synthesis of CD8(+) lymphocytes and proliferative activity of lym phocytes in spleens and tumors. Feeding pregnant or lactating mothers with the 15% olive-oil diet had no marked tumor-protective effect on chemical ly -induced colon cancer in offspring. Diet-dependent changes were found at th e cellular level. In the spleen of control offspring, the presence of a tum or was accompanied by an increase in the number of Ki-67 cells and CD8(+) l ymphocytes in the red pulp. In experimental group 1, DMH significantly incr eased the total cell number and the number of CD8(+) lymphocytes in the red pulp of the spleen in both tumor-bearing and tumor-free rats. In experimen tal group II, the total number of lymph cells and the number of CD8(+) lymp hocytes increased compared to offspring fed a control diet. Tumor formation activated the proliferative activity of lymph elements. The total number o f cells in infiltrates of the colon mucosa decreased in tumor-bearing rats compared to tumor-free counterparts, and this was seen in all three dietary rats. In tumors from offspring of experimental group II, only the number o f CD8(+) lymphocytes increased compared to those in offspring of experiment al group I. The findings indicate that feeding mothers the 15% olive-oil di et had a cancer-inhibiting role in offspring, predominately changes at the cellular level.