[A 13-week subchronic toxicity study of bisphenol A in B6C3F1 mice]

A 13-week subchronic toxicity study of bisphenol A (BPA) was performed in male and female B6C3F1 mice at dose levels of 0, 0.2, 0.5, 1.0, 2.0 and 4.0% in the diet, to facilitate dose selection for a subsequent carcinogenicity study. Mice were randomly allocated to 6 groups, each consisting of 10 males and 10 females. Two 0.2% group males and two 4.0% group females died during the experimental period. Suppression of body weight gain and increase in food consumption were observed in males and females of the 4.0% groups. Hematological examination revealed decrease in number of erythrocytes, volume of hemoglobin and value of hematocrit in males and females of the groups receiving 1.0% or above, and an increase in number of platelets in males of 4.0% group. Decrease in number of erythrocytes and hematocrit value was also noticed in females of 0.5% group. Histopathologically, cystic dilatation, degeneration or regeneration of renal tublues were found in males and females of 1.0% or higher groups, multinucleated hepatocytes were increased in mice of both sexes treated with any dose of BPA, and fibrous osteodystrophy was observed in males and females of the 4.0% groups. Based on the results of the present study, it was concluded that the maximum tolerance dose (MTD) of BPA is 0.2% in diet, because the dose level of 0.5% proved to exert significant hematological toxicity.