The metabolic products of Naphthalene produce free radicals and oxidants which can traverse the placenta, blood-brain barrier, and breast milk. This study aimed to evaluate the effect of maternal naphthalene exposure during pregnancy and the lactating period on the development of the cerebrum in rat offspring. There were two main groups in this study; control & treated. The control groups (I) were divided into 4 subgroups: two negatives, where the pregnant rats received no oral gavage (procedure-free controls) and their offspring were sacrificed at postnatal days 7 & 14; and two vehicle controls, where the pregnant rats received oral gavage every other day of corn oil from gestational day 6, then necropsies of their offspring on postnatal days 7 & 14. In the two treated groups (II); II A and IIB; the pregnant rats received oral gavage of 1.3 mg/kg naphthalene every other day from the 6th gestational day, and then their offspring were sacrificed on postnatal days 7 & 14. Cerebral homogenate assay, histological, morphometric, and ultrastructural studies were done to assess naphthalene-related changes in the maturation of the cerebral cortex. Light microscopic examination showed different types of histopathological abnormalities with delayed developmental changes in the layers of the cerebral cortex of naphthalene-treated rats in both age groups. Damage and arrest of maturation of the Gamma-aminobutyric acid neurons of the cerebral cortex were reported. Microstructural damage and undeveloped postnatal synapses were more apparent on the postnatal 14. So, maternal Naphthalene ingestion disrupts the postnatal cerebral development of their offspring.
