Effects of postnatal low-levels of exposure to styrene on behavior and development in rats

Three groups of rats were exposed by inhalation to either clean air (control group) or styrene monomer at 25 and 50 ppm (styrene-exposed groups) for 7 h/day, 6 day/week, from 1 to 48 days of age. Compared to control group, Styrene-exposed groups showed significant delay in the following developmental indices: body weight gain, appearance of pinna detachment and incisor eruption. With respect to open-field activity, the styrene groups indicated longer latency to enter the field, less number of squares crossed and fewer rearings than those of controls. In the avoidance behavior aspect, the styrene groups attained less achievement level in avoidance rates than that of the control group. Dose-related trends were found between the two exposed groups in body weight increment, exploratory and avoidance behavior. Sex differences were seen on these factors also. These results suggest that at postnatal exposure of low-levels to styrene affects behavior and development in rats.