Effects of prenatal styrene exposure on postnatal development and brain serotonin and catecholamine levels in rats

Maternal reproductive effects in Wistar rats exposed to 0, 50, or 300 ppm s tyrene for 6 h/day during gestational days 6 to 20 were evaluated, Their of fspring were observed postnatally for neurochemical changes, growth, and ph ysical landmarks of development. Mothers exposed to styrene were compared w ith pair-fed and ad-lib fed controls in order to adjust nutrient conditions . Prolongation of the gestational period, food intake, and the number of ne onatal deaths or stillbirths in 300-ppm-exposed dams showed evidence of sty rene-related effects. Other reproductive parameters, such as litter size, b irth weight, and sex ratio, were found to exhibit no effects within the var iation range studied. A neurochemical effect was observed in that the 5-HT and HVA concentrations in cerebrum were significantly decreased. Incisor er uption (mandible), eye opening, and the air-righting reflex were delayed in rat pups born to darns receiving 300 ppm styrene exposure compared with th e pair-fed and ad lib control groups. Pups born to dams exposed to 50 ppm s tyrene also had a significantly delayed air-righting reflex compared with a d lib controls, These results suggest that the offspring mere susceptible t o the effects of styrene on a few developmental landmarks even when nutriti onal effects were controlled. (C) 2000 Academic Press.