The expression changes of N-methyl-D-aspartic acid receptor in hippocampus of offspring from female rats exposed to aluminum in the pregnancy and lactation

Abstract

To investigate the effects of aluminum on learning and memory and the expression of N-methyl-D-aspartic acid receptor (NMDAR) of hippocampus in offspring from female rats exposed to Al in the pregnancy or lactation, and to explore the mechanism of toxic effects of Al on central nervous system (CNS) during development. The pregnant Wistar rats were randomly divided into 3 groups based on their body weight, i.e. control group was exposed to distilled water, low exposure group (0.2%AlCl3) and high exposure group (0.4%AlCl3) were exposed orally to AlCl3 in pregnancy and lactation for 6 weeks, 10 rats each group. Aluminum content in blood and brains was determined by atomic absorption spectrophotometry (AAS). Platform experiment was used to detect the abilities of learning and memory. The expression levels of NMDARs were detected by western blot assay. The Al content in blood and brains of rats in exposure groups increased significantly with Al dose, as compared with the control group (P < 0.05). In platform experiment, the incubation periods of rats in low and high exposure groups were (202.71 ± 81.99) and (19.67 ± 8.44) s respectively, which were significantly lower than that [(300.00 ± 0.00) s] in control group (P < 0.01), but the mistake times of rats in low and high exposure groups were 1.43 ± 0.85 and 2.47 ± 0.99 respectively, which were significantly higher than that (0.00 ± 0.00) in control group (P < 0.01). The Al exposure could change the proportion of NMDAR subtypes, the expression levels of NR1 and NR2B in hippocampus of newborn rats in low and high exposure groups were 25.22 ± 0.68, 81.23 ± 15.37 and 24.75 ± 0.71, 56.63 ± 7.82, respectively, which were significantly lower than those (31.69 ± 3.44, 107.61 ± 9.05) in control group (P < 0.05). Aluminum exposure in pregnancy and lactation could reduce the abilities of learning and memory in newborn rats, and change the proportion of NMDAR subtypes. The reduced NR1 and NR2B expression levels may be one of important mechanisms to influence the abilities of learning and memory in offspring.