Effects of Prenatal Rubratoxin-B Exposure on Behaviors of Mouse Offspring

The effects of prenatal rubratoxin-B (RB) exposure on 8 behavioral parameters in JCL:ICR mice were assessed. Pregnant mice were injected intraperitoneally with 0.1 or 0.2 mg/kg/day of RB dissolved in propylene glycol water solution on days 7-9 (Group A) or 10-12 (Group B) of gestation. Controls received the vehicle similarly on days 7-12 of gestation. Before weaning, the offspring of both sexes were examined to test their the surface righting reflex (5 days of age), cliff avoidance response (6 days), negative geotaxis response (7 days), and swimming development (8, 10, and 12 days). After weaning, male animals were examined using the rotarod test (6 weeks of age), the open-field test (7 weeks), the shuttle-box-avoidance-learning test (9 weeks), and the water E-maze test (10 weeks). The preweanling offspring in the 0.2 mg/kg-B group showed significantly lower success rates and longer response times than controls in the cliff-avoidance response. In swimming development, the offspring in the 0.2 mg/kg B group had significantly lower scores than controls for swimming angle at 10 and 12 days of age. The avoidance learning of the mice in all RB-exposed A and B groups was significantly poorer than that of controls. These results indicate that prenatal exposure to RB produced a delay of early response development and impaired learning ability in the offspring of mice exposed to RB during middle pregnancy.