Lead is toxic to all organ systems. Central nervous system has received much attention because of the impact of lead exposure on cognitive and behavioral development in children. We investigated the effects of in utero lowdose exposure to lead on neurogenesis in hippocampus and spatial learning and memory in young rats. Wistar rats, after establishing pregnancy, were given drinking water with 0.1% lead acetate until parturition. Control animals received deionized water. The hippocampus of lead-exposed rats showed significantly higher level of lead when compared to age matched controls on postnatal day 0, 21, 30, 40 and 50. Spatial learning and memory determined with Morris water maze test revealed significant memory deficit in lead exposed rats when tested on postnatal day 21 and deficit in relearning ability on postnatal day 37. It also revealed significant memory deficit in lead exposed rats when tested on postnatal day 30, but good relearning ability on postnatal day 47. Doublecortin immunostaining showed significantly decreased number of new neurons in the lead-exposed rats in comparison to control rats. Our data show that low-dose exposure to lead during pregnancy decreased neurogenesis in the hippocampus of young rats that resulted in impairment of spatial learning and memory.
Hussain M Al-Shimali, Ahmad F Al-Musaileem, Muddanna S Rao and Khalid M Khan