Abstract
This investigation was carried out to determine the effects of aflatoxin B1 (AFB1) on fetuses of mice and rats, and maternal tissues of rats. The pregnant ICR mice were injected intraperitoneal (ip.) at Day-13 of gestation with AFB1 at 20 and 10 mg/kg BW (body weight). The fetuses from mice were examined at 12, 24 and 48 hours after inoculation (HAI). The pregnant Wistar rats were also injected ip. at Day-13 of gestation with AFB1 at 20 mg/kg BW (sacrificed at 12 HAI), 5mg/kg BW (sacrificed at 24 HAI) and 2.5mg/kg BW (sacrificed at 48 HAI). Fetuses, placenta, and maternal liver, thymus and spleen were collected from rats for histopathology, the in situ detection of apoptotic cells (TUNEL method) and immunohistochemistry. Light microscopic study on fetuses of mice, and placenta and fetuses of rats detected no difference of cell death in AFB1-treated group and in control group examined at different time points of study. On the contrary, liver, spleen and thymus of rats treated with AFB1 at different doses of different time points evoked cell death where the lesions of spleen and liver were striking at 24 and 48 HAI, respectively. The lesions of liver were characterized by severe congestion, fatty change and multifocal/diffuse cell death; and at early time these hepatocytes underwent apoptotic type of cell death . The lesions of liver characterized by necrosis with slight apoptotic cells increased in severity with the advancement of time. The striking pyknotic cell death in thymus was evident at 48 HAI. These pyknotic cells showed positive staining with TUNEL method, the in situ detection of apoptotic cells. Immunohistochemistry detected activated caspase-3 in pyknotic cells of spleen, liver and thymus. However, the relation between AFB1-induced apoptosis, necrosis and tumorigenesis in rats should be elucidated.
