Metformin Attenuates Behavioral Deficits and Oxidative Stress in a Preclinical Model of Autism

Autism spectrum disorder (ASD) is a complex neurodevelopmental condition lacking effective pharmacological treatments. Metformin has emerged as a candidate for drug repurposing in ASD due to its metabolic and neurobiological actions. This study evaluated the in vivo effects of metformin (400 mg/kg, orally) administered from postnatal day 21 to 35 (PND21-35) in male and female offspring of mice prenatally exposed to valproic acid (VPA; 450 mg/kg, i.p.) on gestational day 12.5 (GD12.5). Behavioral tests included the open field, elevated plus maze, Y-maze, three-chamber social interaction, and self-grooming. The prefrontal cortex (PFC) and hippocampus (HPC) were analyzed for oxidative stress markers (malondialdehyde [MDA], reduced glutathione [GSH]), total protein content, and acetylcholinesterase (AChE) activity. In vivo, metformin attenuated several VPA-associated behavioral alterations, including changes in locomotor/exploratory activity and repetitive behavior, with additional effects on anxiety-like behavior, sociability, and spatial working memory that varied according to sex and behavioral parameter. Biochemical analyses showed metformin-associated changes in GSH and MDA that varied across sexes and brain regions. VPA-induced increases in PFC AChE activity were attenuated by metformin in both sexes. Total protein content also varied according to sex and brain region. These findings provide preclinical evidence that metformin can attenuate behavioral alterations associated with prenatal VPA exposure and modulate oxidative stress-related markers, with patterns varying across sexes and brain regions.