Effect of X-ray exposure on soluble tumor necrosis factor receptor-p75 release in hepatocellular carcinoma HepG2 cells in vitro

Objective To investigate the effects of X-ray exposure on the release of soluble tumor necrosis factor receptor-p75 (sTNFR-p75) in hepatocellular carcinoma HepG2 cells in vitro. Methods Enzyme-linked immunosorbent assay (ELISA) was used to examine the levels of sTNFR-p75 in the supernatants of HepG2 cells before and after X-ray exposure. The cell apoptosis was analyzed by flow cytometry and transmission electron microscope (TEM), and the morphological changes of the cells were examined under optical microscope and transmission electron microscope (TEM). Results X-ray exposure of the cells resulted in a strong increase of cell apoptosis (P0.05) and sTNFR-p75 production in the cells as compared with the those before the exposure (P0.01). Optical microscopy revealed apoptotic changes of HepG2 cell after the exposure, shown as cell shrinkage, spherical cell morphology, cytoplasmic and nuclear condensation. Apoptotic bodies were detected by TEM. Conclusion X-ray exposure induces HepG2 cells apoptosis by inhibiting the release of sTNFR-p75 into the supernatant.