Proteomic Analysis of Thin Filament Components Elucidates Changes in Spastic Muscle Sarcomere After Stroke

This study analyzed the changes in the composition of thin filaments in spastic muscles after stroke to investigate the mechanism underlying changes in the sarcomeres. Twenty-four rats were randomly divided into four groups: normal, and 3, 6, and 9 days after stroke. A model of post-stroke gastrocnemius muscle spasm was created. Quantitative proteomic procedure and bioinformatics analysis revealed significant changes in cytoskeletal protein expressions in gastrocnemius muscles of each stroke group, particularly those on thin filaments. On the 3rd day after stroke, proteins upregulated within the thin filaments included actin-binding LIM protein 1, tropomyosin 3, leiomodin 2, drebrin-like protein, parvin beta, capping actin protein-gelsolin like, actinin alpha 2, and PDZ-LIM-domain protein 1, while downregulated proteins included tropomyosin 1, gelsolin, actinin alpha 3, and PDZ-LIM-domain protein 7. On the sixth day, upregulation of tropomyosin 2 was newly added while parvin alpha, destrin, PDZ-LIM-domain protein 3, leiomodin 3 were downregulated. On the 9th day, actinin alpha 2, PDZ-LIM-domain protein 7, and cofilin 2 were downregulated. These altered proteins are capable of promoting actin filament elongation and regulating Z-disc growth, and changes in their expression may be responsible for the changes in spastic muscle sarcomere after stroke.