Lanthanum chloride impairs memory, decreases pCaMK IV, pMAPK and pCREB expression of hippocampus in rats.

Surveys have reported that rare-earth elements (REEs) could impair cognitive functions of children. Experimental studies have shown the neurological adverse effects of REEs on animals. However, the mechanism underlying these impairments is unclear. Lanthanum is often selected to study the effects of REEs. The purpose of this study was to investigate the memory impairment induced by lanthanum chloride (LaCl3) exposure and the possible mechanism from the aspects of expression of CREB signal pathway and synaptic ultrastructure in the hippocampus. Lactational rats were exposed to 0%, 0.25%, 0.50%, and 1.0% LaCl3 in drinking water, respectively. Their offspring were exposed to LaCl3 by parental lactation for 3 weeks and then administrated with 0%, 0.25%, 0.50% and 1.0% LaCl3 in drinking water for 1 month. The results showed that 0.25%, 0.50%, and 1.0% LaCl3 exposure could significantly impair memory of young rats. Hippocampal pCaMK IV, pMAPK, pCREB, c-fos and egr1 expression were decreased significantly, and synaptic ultrastructure was negatively affected after LaCl3 exposure. These results indicate that LaCl3 exposure impairs memory of rats and this impairment may be attributed to the lower levels of pCaMK IV, pMAPK, pCREB, c-fos and egr1 expression and change of synaptic ultrastructure in hippocampus.