LAUSR

Aims: To investigate the effect of FTY720 on the valproic acid (VPA) rat model of autism. Main methods: As an animal model of autism, we used intraperitoneal injection of VPA on embryonic day 12.5 in Wistar rats. The pups were given FTY720 orally at doses of 0.25, 0.5 and 1 mg/kg daily from postnatal day 15 to 35. Social behavior, spatial learning and memory were assessed at the end of FTY720 treatment. The histological change, oxidative stress, neuroinflammatory responses, and apoptosis‐related proteins in the hippocampus were evaluated. Key findings: FTY720 (1 mg/kg) administration to VPA‐exposed rats (1) improved social behavior, spatial learning and memory impairment; (2) resulted in a reduction in neuronal loss and apoptosis of pyramidal cells in hippocampal CA1 regions; (3) inhibited activation of microglial cells, in turn lowering the level of pro‐inflammatory cytokines interleukin‐1&bgr; (IL‐1&bgr;) and IL‐6 in the hippocampus; (4) changed Malondialdehyde (MDA) levels, Glutathione (GSH) levels, superoxide dismutase (SOD) activity and Glutathione Peroxidase (GSH‐Px) activity in the hippocampus; (6) inhibited the elevated Bax and caspase‐3 protein levels and enhanced the relative expression level of Bcl‐2 in the hippocampus; and (7) increased phospho‐Ca2 +/calmodulin‐dependent protein kinase II (p‐CaMKII), phospho‐cAMP‐response element binding protein (p‐CREB) and Brain Derived Neurotrophic Factor (BDNF) protein expression in the hippocampus. Significance: FTY720 rescues social deficit, spatial learning and memory impairment in VPA‐exposed rats. FTY720 exerts both a direct protection for neurons and an indirect modulation of inflammation‐mediated neuron loss as a possible mechanism of neuroprotection.