Changes of cerebellar cortex in a valproic acid-induced rat model of autism

Area of Science:

• Neuroscience
• Developmental Biology
• Toxicology

Background:

• Valproic acid (VPA) is a widely used anticonvulsant and mood-stabilizing drug.
• Prenatal and early postnatal exposure to VPA has been linked to neurodevelopmental abnormalities.
• The cerebellum plays a critical role in motor control, coordination, and cognitive functions.

Purpose of the Study:

• To investigate the effects of VPA administration on the cellular structure of the rat cerebellum.
• To analyze changes in neuronal density, nuclear size, and synaptic organization in response to VPA exposure.

Main Methods:

• Male Sprague-Dawley rats were administered VPA (600 mg/kg) or saline on embryonic day 15 and postnatal day 11.
• Cerebellar tissues were collected on postnatal day 30 for light and electron microscopy.
• Quantitative analyses included numerical cell density, mean nuclear diameter, and synaptic parameters.

Main Results:

• VPA exposure led to an increased numerical density of cerebellar granule cells and a decreased density of Purkinje cells.
• Granule cells exhibited a smaller mean nuclear diameter in one experimental group, while Purkinje cells showed this in both experimental groups.
• The numerical density and mean diameter of synaptic disks in the cerebellar granular layer were significantly reduced in VPA-exposed rats.

Conclusions:

• Prenatal or early postnatal VPA administration significantly alters the number of neurons and synapses in the developing rat cerebellum.
• These structural changes in the cerebellum may contribute to the neurodevelopmental risks associated with VPA exposure.