Triple-phase VPA administration in Sprague-Dawley rats: A cost-effective ASD model unveiling the synaptic-mitochondrial-inflammatory axis as a therapeutic target.

Scientists created a better way to study autism using lab rats by giving pregnant rats a medicine called valproic acid in three smaller doses instead of one large dose. This kept the mother rats healthier while still creating autism-like behaviors in their babies, including trouble with social interaction and repetitive behaviors. The researchers found problems with brain cell connections, energy-producing parts of cells, and inflammation that could be targets for future autism treatments.

Researchers developed an improved animal model of autism using a three-phase valproic acid (VPA) administration protocol in rats. This approach eliminated maternal deaths and improved survival rates while successfully creating autism-like behaviors including social deficits, repetitive behaviors, and delayed development. The study identified disruptions in brain synapses, mitochondria, and inflammatory processes as key mechanisms. Compared to traditional single-dose models, this method showed better safety and reliability while maintaining strong autism-like characteristics.

The findings suggest the synaptic-mitochondrial-inflammatory axis as a potential therapeutic target for autism interventions.

Provides improved research platform for testing autism interventions. The identified synaptic-mitochondrial-inflammatory pathway offers potential therapeutic targets, though translation to human treatments requires further validation through clinical studies.

Study conducted only in animal models with unclear sample sizes. Long-term behavioral outcomes and translational validity to human autism not established. Limited to specific VPA-induced autism model which may not represent all autism subtypes.

To overcome limitations of traditional single-dose valproic acid (VPA) models in autism spectrum disorder (ASD) research-including severe maternal toxicity and imprecise embryonic exposure-this study established a cost-effective ASD model using a three-phase sequential VPA strategy in Sprague-Dawley (SD) rats. Pregnant SD rats received VPA (400 → 450 → 400 mg·kg) on gestational days 11.5, 12.5, and 13.5. Maternal/neonatal survival, neurodevelopmental milestones, and behavioral phenotypes (open field, three-chamber sociability, repetitive grooming) were assessed. Synaptic ultrastructure (transmission electron microscopy), neuroinflammation (ELISA for IL-1β, IL-6, TNF-α, IL-10), and oxidative stress (CAT, SOD, GSH-Px, MDA) in the prefrontal cortex were analyzed.

The optimized protocol eliminated maternal mortality (p < 0.01) and resorption (p < 0.0001), while enhancing neonatal survival (p < 0.01) and litter size (12-16 pups). Model rats exhibited core ASD phenotypes: social deficits (p < 0.0001), repetitive grooming (P < 0.01), and delayed neurodevelopment. Synaptic vesicle depletion, mitochondrial cristae disruption, proinflammatory cytokine upregulation (p < 0.01), and antioxidant suppression (p < 0.01) confirmed synaptic-mitochondrial-inflammatory axis dysregulation. SD rats outperformed C57BL/6 mice in phenotypic fidelity and modeling efficiency.

This study pioneers a three-phase VPA strategy that balances high ASD phenotyping fidelity with animal welfare. The synaptic-mitochondrial-inflammatory axis is identified as a novel therapeutic target. SD rats provide a superior, cost-effective platform for ASD mechanism and intervention studies.