id_683. CHANGES IN THE SYNAPTIC PLASTICITY AND EXCITABILITY OF SOMATOSENSORY CORTEX IN A MOUSE MODEL OF AMYOTROPHIC LATERAL SCLEROSIS AFTER SWIM TRAINING
Anbarieh Saadat1, Małgorzata Jasińska2, Bartosz Cedro3, Alicja Piekarska3, Damian Flis3, Wiesław Ziółkowski4, Elżbieta Pyza1
1 Department of Cell Biology and Imaging, Jagiellonian University, Kraków, Poland
2 Department of Histology, Jagiellonian University Medical College, Kraków, Poland
3 Department of Pharmaceutical Pathophysiology, Medical University of Gdańsk, Poland
4 Department of Rehabilitation Medicine, Medical University of Gdańsk, Poland
INTRODUCTION: Amyotrophic Lateral Sclerosis (ALS) is a progressive and incurable neurodegenerative disease, and treatments such as physical activity are focused on managing and reducing the symptoms of the disease. The hyperexcitability in the somatosensory cortex is observed during the presymptomatic stage of ALS.
AIM(S): This study aimed to understand how excitation develops throughout the disease and whether swim training has any effect on hyperexcitation.
METHOD(S): Here, we analysed the density of excitatory and inhibitory synapses, their ratio (E/I), and dendritic spine morphology in the B2 barrel of the somatosensory cortex in female SOD1G93A mice using transmission electron microscopy. ALS mice were divided and analysed before the onset of the disease, at the onset, and at the terminal stage with, and without swim training. Swim training was applied after the first onset of symptoms.
RESULTS: The obtained results showed an increase in the density of excitatory synapses in the presymptomatic ALS mice, consistent with early cortical hyperexcitability. At disease onset, we detected an increase in inhibitory synapses, suggesting a compensatory mechanism that may act to stabilise network activity. Dendritic spine morphology also changed across stages, reflecting structural remodelling accompanying the evolving synaptic imbalance. Swim training reduced excitatory synapse density and lowered the E/I ratio in symptomatic ALS mice, indicating a shift toward decreased cortical excitation.
CONCLUSIONS: Our data confirm cortical hyperexcitability and changes in the synaptic balance in female ALS mice and suggest the potential benefit of swim training as an activity-based strategy for managing cortical dysfunction in ALS.
FINANCIAL SUPPORT: NCN OPUS 20 nr UMO-2020/39/B/NZ7/03366 to WZ and EP