The synergistic effect of benzo[a]pyrene and lead on learning and memory of mice.

In the present study, the single and combined neurotoxic effects of benzo[a]pyrene ([BaP] 0.0, 0.5, and 5.0 mg/kg body weight; intragastric administration) and lead acetate (0.0, 5.4, and 54.0 mg/L; by drinking water) were examined on KunMing mice. In the Morris water maze, results showed that BaP and lead induced synergistic effects on the escape latency and the time spent in the target quadrant but also showed an additive effect on the number of times animal crossing the original platform. Also, BaP and lead induced a synergistic effect on DNA damage in the single-cell gel electrophoresis. However, BaP plus lead showed additive effects on the levels of malondialdehyde, superoxide dismutase, and glutathione. These results suggested that the combination of BaP and lead can lead to a synergistic effect on spatial learning and memory impairments, and the mechanisms of the synergistic effects on behavioral deficits may be due to the oxidative stress injury.