Research Of Ionizing Radiation Effect On Human Umbilical Vein Endothelial Cells

Background and ObjectiveOsteoradionecrosis of jaw(ORNJ) is a common complication of malignant tumors of the head and neck after the radiotherapy because of the radiation damage to jaw bones. With the influences of infection or damage, it leads to the suppuration of the tissue, the fistulization, the exposure of the bone, the un-healing would, and finally facial malformation. All of them make a serious effect on patient's life. However, the mechanism of ORNJ is still unclear known. It is significant to study the mechanism of radiation damage to jaw bones for active prevention and treatment and improve the life quality after radiotherapy as well.The etiology and pathology of ORNJ is controversial. Themechanism raised by Marx, the theory of three hypo-condition of tissue (hypo-cell, hypo-blood-vessel and hypoxia) from radiation damage, is generally accepted. The pathological basis of ONRJ is the change of osseous tissue and vascular tissue structure. To provide the theoretical evidence for ORNJ, HUVE-12 was observed with the changes of the secretion of VEGF and bFGF, the cytoskeleton and cell ultrastructure after exposed to various dose of radiation in this study.Materials and MethodsHUVE-12 cultivated in vitro were radiated with 60Co γ ray in different dose, ranging from 0-12Gy, the cytoskeleton were observed by Confocal Laser Scanning Microscope 6hs after the radiation . The ultrastructure was observed with ransmission electron microscope 24hs later. The cytoskeleton protein f-actin were detected with flow cytometry 12hs, 24hs after radiation. And the VEGF, bFGF were detected with flow cytometry 6hs, 12hs, and 24hs after radiation.ResultsHUVE-12, well cultivated in vitro, changed as the increase of radiation dose. The mitochondria swell and the increase of pinosome in cells was found under the electron microscope. Meanwhile, the W-P small body increased with the increase of radiation dose rate. The destruction of the cytoskeleton was observed with the ConfocalLaser Scanning Microscope, and it was more severe as the radiation dose increasing detecting by the flow cytometry, as the increase of radiation dose the f-actin decreased and it was in the lowest level in 12hs after the radiation. But it seemed to have some recovery 24hs later. Meanwhile, the VEGF increased at the 2Gy and 4Gy, and bFGF increased at 2^ 4> 6Gy, then both of them decreased directly to the negative level depending the dose increasing.Conclusion1. Ionizing radiation may make damage to the HUVE-12, with the radiation dose rate increase, the damage of HUVE-12 is more and more obviously.2. The W-P small body of HUVE-12 increased with the increase of radiation dose rate. It may be one of the mechanisms on the earlier inflammation and thrombus in the tissue after the radiation.3. The cytomembrane skeleton of HUVE-12 may be destroyed by ionizing radiation. This effect may be more and more severe as the radiation dose increased with the time-dependent. The polymerization and depolymerization of F-actin, the protein of the cytoskeleton have the balance 24hs after the radiation. This may be probably related with the exudation and swell of the tissue inflammatory reaction during the early stage of injury.4. VEGF and bFGF could be secreted by HUVE-12 after low doseradiation. This may make the HUVE-12 radiation resistance in low dose radiation.