Neurotoxic Effect of Benzo[a]pyrene and Its Possible Association with 6-Hydroxydopamine Induced Neurobehavioral Changes during Early Adolescence Period in Rats.

Abstract

Exposure to persistent genotoxicants like benzo[a]pyrene (B[a]P) during postnatal days causes neurobehavioral changes in animal models. However, neurotoxic potential of B[a]P and its association with 6-hydroxydopamine (6-OHDA) induced neurobehavioral changes are yet to be explored. The growth of rat brain peaks at the first week of birth and continues up to one month with the attainment of adolescence. Hence, the present study was conducted on male Wistar rats at postnatal day 5 (PND 5) following single intracisternal administration of B[a]P to compare with neurobehavioral and neurotransmitter changes induced by 6-OHDA at PND 30. Spontaneous motor activity was significantly increased by 6-OHDA showing similar trend following B[a]P administration. Total distance travelled in novel open field arena and elevated plus maze was significantly increased following B[a]P and 6-OHDA administration. Neurotransmitter estimation showed significant alleviation of dopamine in striatum following B[a]P and 6-OHDA administration. Histopathological studies of striatum by hematoxylin and eosin (H&E) staining revealed the neurodegenerative potential of B[a]P and 6-OHDA. Our results indicate that B[a]P-induced spontaneous motor hyperactivity in rats showed symptomatic similarities with 6-OHDA. In conclusion, early postnatal exposure to B[a]P in rats causing neurobehavioral changes may lead to serious neurodegenerative consequences during adolescence.