Abstract
Yogurt consumption has been associated with decreased risk of colon cancer. The apoptosis induced by yogurt as a mechanism involved in the inhibition of an experimental intestinal tumor induced by 1,2 dimethylhydrazine (DMH) in BALB/c mice, has been studied. An imbalance between apoptosis and mitosis or cell proliferation is believed to underlie colon cancer development and progression. We determined the effect of yogurt feeding in the induction of apoptosis and the relationship between mitosis and apoptosis in mice injected with the carcinogen DMH and in mice injected with DMH and fed with a diet supplemented with yogurt. The percentage of mitotic and apoptotic cells was analyzed every 2 weeks from week 8 to 16. They were analyzed on histological slices from the large intestine by colchicine, or Tunel test for mitosis and apoptosis determination, respectively. An increase in the mitosis during the first 4 weeks of tumor development with apoptosis negative and severe dysphasia, was observed in animals treated with the carcinogen. In those animals that received DMH and were given yogurt, a moderate cell proliferation with a significant increase in the number of apoptotic cells was determined. The increase in the apoptotic activity was also observed in the group of animals that received only a diet supplemented with yogurt. The results suggest that yogurt would influence the balance between mitosis and apoptosis, which was modified during the carcinogenesis process, by increasing cellular apoptosis. Dietary supplementation of yogurt may play a role in modulating cell proliferation or apoptosis during the development of colorectal carcinoma.