Restoring Brain Function in Autism: GSK3β Inhibition by 6-Bromoindirubin-3′-oxime Reverses Valproic Acid-induced Neuropathology

Autism spectrum disorder (ASD) is a complex neurodevelopmental condition characterized by social deficits, restricted interests, and repetitive behaviors. Although aripiprazole and risperidone are FDA-approved for ASD, they primarily target comorbid symptoms and are associated with significant side effects. This study aimed to investigate the effects of 6-bromoindirubin-3'-oxime (6BIO), a glycogen synthase kinase 3β (GSK3β) inhibitor, in a VPA model of ASD. Pregnant Wistar rat dams received a single intraperitoneal (ip) injection of VPA (600 mg/kg) or an equal volume of saline on GD 12.5. Offspring prenatally exposed to VPA showed impairments in early age observations, such as nervous reflex, motor coordination, sensory function, and developmental milestones. On postnatal day (PND), 23 male and female offspring were separated and randomly assigned to receive either risperidone (2.5 mg/kg, po) or 6BIO (15 or 30 μg/kg, ip) daily until PND 82. Systemic postnatal administration of 6BIO dose-dependently ameliorated anxiety-like behavior, exploratory, social deficit, repetitive behavior, spatial cognition, recognition memory, motor coordination, gastrointestinal motility, brain edema, and blood-brain barrier functions. Furthermore, chronic 6BIO postnatal treatment significantly attenuated VPA-induced neuronal damage in the prefrontal cortex, hippocampus, and cerebellum. 6BIO also significantly suppressed the upregulated cytosolic GSK3β phosphorylation, as determined by immunohistochemistry and Western blotting. Additionally, 6BIO modulated mRNA expression levels of Wnt, CHD8, SHANK3, GAD65, and 67, and transcriptional factors such as β-catenin and NLGN3 were altered by prenatal VPA exposure. In conclusion, these findings suggest that 6BIO may exert neuroprotective effects via GSK3β inhibition, indicating its potential as a candidate compound for therapeutic intervention in ASD.