Protective role of soybean feeding against the cytogenetical and histopathological effects of dibutylamine and sodium nitrate on bone marrow and liver of mice.

The protective role of soybean feeding against the cytogenetic and histopathologic effects of the nitrosamine precursors sodium nitrate and dibutylamine was evaluated. Treated animals were killed every 3 months, over a period of 15 months, and bone marrow cells were prepared for cytogenetic studies and livers for histopathological observations. Structural chromosomal aberrations and mitotic indices increased after treatment with the nitrosamine precursors for all tested times. Livers were within the normal appearance during the first 6 months. After that a mild, moderate, marked dysplasia with lymphocytic infiltration, fatty vacuolation and liver atrophy was observed. Soybean coadministered with the nitrosamine precursors reduced the number of structural chromosomal aberrations. Mitotic indices decreased at all tested groups but still higher than the control level. A marked reduction in dysplastic features in the liver cells was observed. In conclusion, the cytogenetic and histopathologic results of this study strongly support the protective role of soybean against the genotoxic and carcinogenic action of nitrosomine formed in vivo from its precursors.