Abstract: ObjectiveTo investigate the impact of lead exposure during the pre-and post-natal period on gene expression of hippocampus in developmental rats in vivo with cDNA microarray.MethodsPregnant Sprague-Dawley rats at(18±0.5)days of gestation were administered lead acetate(0.2%)in their drinking water.Dosing began 3 days prior to breeding and continued until their pups were weaned at 21 days.At the time of weaning,blood lead level of pups were examined and hippocampus of pups were dissected.Total RNA was isolated and treated according to specific instructions.Nylon membrane was used as the array base.Oligonucleotide probes were synthesized and spotted onto the nylon membrane to explore the variation of gene expression.ResultsLead-exposed rats had higher blood lead level than controls(3.41±0.27)μmol/L vs (0.29±0.06)μmol/L,P<0.05.120 up-regulated and 10 down-regulated genes were identified by cDNA microarray, Pb/C score greater than 2 or less than 0.5 were considered the significantly altered genes after specific treatment in the study.ConclusionLead exposure during late gestation and lactation period may influence learning and memory of rat due to changes of some differentially expressed genes.