AFM analysis of spatial elastic modulus distribution of fibroblast surface after radiation exposure.

The mechanical properties of cells, determined mainly by the properties and structure of the cytoskeleton, are heterogeneous at the micro- and nanoscale. The spatial distribution of mechanical parameters such as elastic modulus and adhesion force over the surface of fibroblasts characterizes their mechanical phenotype. By mapping mechanical properties using the Force Volume mode of atomic force microscopy and using statistical analysis methods (modeling parameter distributions with a two-component Gaussian mixture and clustering data), patterns of changes in the spatial distribution of the mechanical properties of the fibroblast surface of primary cultures isolated from the lungs of non-irradiated and irradiated 14-month-old Wistar rats and a 3-week post-radiation period were established. After irradiation, the proportion of surface areas with increased elastic properties and reduced adhesive properties corresponding to the plasmalemma areas above the structures of stress fibers changes. The findings indicate that irradiation at both low (0.1 Gy) and high (1 and 15 Gy) doses induces alterations in the mechanical phenotype of fibroblasts during the early late post-radiation period. These characteristic modifications in fibroblast mechanics may represent early biomarkers of radiation-induced complications, such as radiation fibrosis.