Effects Of Heavy Ion And X-ray Irradiation On The Cytoskeleton And Cytomechanics Of Cortical Neurons

Objective:To study the effects of heavy ion and X-ray on the cytoskeleton and cytomechanics of cortical neurons and discuss its possible damage mechanism in the cranial radiation therapy.Materials and Methods:The cortical neurons of new-born BALB/C mouse were primary cultured.7days later, the neuronal cells were irradiated with heavy ion at2Gy and X-ray at4Gy, respectively. The inverted phase contrast microscopy was used to observe the alertions of celluar morphology. The immunofluorescence microscopy was used to detect the changes of cell number, cytoskeletal morphology and expression of β-tubulin Ⅲ. The atomic force microscopy (AFM) was used to measure the cellular surface topographies and Young’s modulus.Results:1. The morphological characterizations via inverted phase contrast microscopy revealed that, heavy ion irradiation group decreased in cellular number and the connections between cells. However, the X-ray irradiation group survived fewer neurons and more cell debris with the majority of axons’connecting fractured.2. The data of immunofluorescence assay showed that, the cell density decreased significantly (P<0.01) after heavy ion irradiation. Most neurons were fusiform with cytoplasmic shrinkage and shorter axons. Nevertheless, in the X-ray irradiation group, cells’density decreased more dramatically (P<0.01) and a wealth of axonal fractures appeared. Moreover, neurons were shrinking with less distribution of microtubules and chromatin condensation appeared.3. The AFM imaging on the topological features of neuronal cells radiated by heavy ion had increased prominences on surface. In the X-ray irradiation group, it could be observed that the cytoskeletal protein structures had become disorder or even collapse. Furthermore. The Young’s modulus of neurons increased after heavy ions irradiation (P＜0.01) and the X-ray group rose more significantly (P＜0.01).Conclusion:A dose of irradiation can lead to changes in neuronal cytoskeleton and cytomechanics. However, the radiation injuries caused by X-ray were much more severer than heavy ion, which were in agreement with the results that heavy ion may have potential advantages over X-ray in radiation therapy.