Postweaning exposure to lanthanum alters neurological behavior during early adulthood in rats

Lanthanum is a rare-earth element that has been used in various fields including medicine, agriculture and industry. Previously, in utero lanthanum exposure to dams was shown to alter neurobehavior and neurotransmitter levels in rat offspring; however, the effects of postweaning exposure to lanthanum on neurological behavior is still limited. The purpose of this study was to investigate the effects of postweaning exposure to lanthanum on neurological behavior during early adulthood in rats. Rats were orally exposed to 0, 2, 20, 60 mg/kg BW of lanthanum nitrate from postnatal day (PND) 24 to PND60. Our results indicated that lanthanum treatment significantly decreased body weight and food intake. Morris water maze test results showed that lanthanum significantly decreased escape latency and travel distance. Lanthanum treatment also significantly decreased grip strength, hindlimb strength, and running time & distance in motor activity test. Further results showed that lanthanum treatment significantly decreased plasma neurotransmitter levels of acetylcholine and norepinephrine as well as the number of neurons in the CA1 area of the hippocampus. These results suggest that postweaning exposure to lanthanum have adverse effects on neurobehaviors and the central nervous system, with no-observed-adverse-effect level at 2 mg/kg BW and benchmark dose lower confidence limit at 1.7 mg/kg BW.