D-serine reduces memory impairment and neuronal damage induced by chronic lead exposure.

Although exogenous D-serine has been applied as a neural regulatory intervention in many studies, the role played by D-serine in hippocampal injuries caused by lead exposure remains poorly understood. Rat models of chronic lead exposure were established through the administration of 0.05% lead acetate for 8 weeks. Simultaneously, rats were administered 30 or 60 mg/kg D-serine, intraperitoneally, twice a day. Our results showed that D-serine treatment shortened the escape latency from the Morris water maze, increased the number of times that mice crossed the original platform location, and alleviated the pathological damage experienced by hippocampal neurons in response to lead exposure. Although D-serine administration did not increase the expression levels of the N-methyl-D-aspartate receptor subtype 2B (NR2B) in the hippocampi of lead-exposed rats, 60 mg/kg D-serine treatment restored the expression levels of NR2A, which are reduced by lead exposure. These findings suggested that D-serine can alleviate learning and memory impairments induced by lead exposure and that the underlying mechanism is associated with the increased expression of NR2A in the hippocampus. This study was approved by the Animal Ethics Committee of North China University of Science and Technology, China (approval No. LX2018155) on December 21, 2018.