Low‑dose X‑ray irradiation induces morphological changes and cytoskeleton reorganization in osteoblasts

Abstract

Recently, research into the biological effects of low dose X-ray irradiation (LDI) has been a focus of interest. Numerous studies have suggested that cells exhibit different responses and biological effects to LDI compared with high doses. Preliminary studies have demonstrated that LDI may promote osteoblast proliferation and differentiation in vitro, thereby accelerating fracture healing in mice. However, the exact mechanism of action by which LDI exerts its effects remains unclear. Previous studies using microarrays revealed that LDI promoted the expression of genes associated with the cytoskeleton. In the current study, the effect of X-ray irradiation (0.5 and 5 Gy) on the morphology of MC3T3-E1 cells and fiber actin organization was investigated. Osteoblasts were treated with 0, 0.5 and 5 Gy X-ray irradiation, following which changes in the actin cytoskeleton were observed. The levels of RhoA, ROCK, cofilin and phosphorylated-cofilin were measured by reverse transcription-quantitative PCR and western blotting. Subsequently, osteoblasts were pretreated with ROCK specific inhibitor Y27632 to observe the changes of actin skeleton after X-ray irradiation. The results demonstrated that the cellular morphological changes were closely associated with radiation dose and exposure time. Furthermore, the gene expression levels of small GTPase RhoA and its effectors were increased following LDI. These results indicated that the RhoA/Rho-associated kinase pathway may serve a significant role in regulating LDI-induced osteoblast cytoskeleton reorganization.

Cytoskeleton Response to Ionizing Radiation: A Brief Review on Adhesion and Migration Effects

“…Huang et al examined the alterations in the CSK of osteoblasts after the delivery of 0.5 Gy X-ray radiation [ 89 ]. Notably, the study reported changes in the structure of intracellular actin.…”

“…Furthermore, the authors investigated the expression of proteins, such as RhoA, ROCK1, and p-cofilin, which stimulate the reorganization of the CSK due to actin depolymerization [ 90 ]. These proteins were involved in the reorganization of the actin filaments after the delivery of radiation, effectively proving that they manage the dynamics behind the regulation of the actin CSK [ 89 ].…”

Effects of environmental stress factors on the actin cytoskeleton of fungi and plants: Ionizing radiation and ROS

“…Concerning mammalian cells several studies report that low‐dose IR (<5 Gy) affects actin‐dynamics leading to reorganization of the actin cytoskeleton (Huang et al, 2020; Huang, Chai, Wang, Sun, & Xu, 2021; Jasinska‐Konior et al, 2019).…”

Stereotactic Body Radiotherapy and Conventional Radiotherapy Induce Cytoskeleton Extension and Enlargement of Cell Morphology in Non-Small Cell Lung Cancer

“…11 Cytoskeleton rearrangement is the structural basis for the exchange of intracellular and extracellular information after radiation. 12 The cytoskeleton is mainly composed of actin microfilaments, and provides a mechanical support framework for maintaining cell morphology, and endothelial integrity and repair. 13 The cytoskeleton also plays a vital role in cell adhesion, proliferation, motility, differentiation, division, etc.…”