Elastic properties and collagen-synthesizing activity of pulmonary fibroblasts after external irradiation of rats at doses of 0.1–15 Gy

Radiation fibrosis is one of the serious complications of radiation therapy that develops over a long period after exposure. The molecular and cellular mechanisms leading to the development of this pathology take place at a much earlier time. Ionizing radiation changes the properties and functions of fibroblasts, the primary cells of connective tissue that produce extracellular matrix proteins. The study aimed to identify, using atomic force and fluorescence microscopy methods, patterns of radiation-induced changes in the elastic modulus of the pulmonary fibroblast surface, the level of collagen production by cells and their relationship following localized thoracic X-ray irradiation in rats and a 3-week post-exposure period. The formation of a dose-dependent mechanical phenotype of fibroblasts has been established, due to both changes in the structure of the actin cortex and the formation of stress fibers in the nuclear zones of cells. It has been shown that the formation of a radiation-induced mechanical phenotype of fibroblasts correlates with their collagen-synthetic ability, which suggests an internal mechanism of influence of the mechanical properties of cells in the nuclear zone on collagen production. The data obtained deepen the understanding of the molecular and cellular mechanisms of radiation fibrosis development.