Background: The aim of this study was to investigate the effects of Saikosaponin-d (SSd) combined with radiotherapy on SMMC-7721 hepatoma cell lines and its mechanism.
Material and Methods: SMMC-7721 hepatoma cell lines are selected in our research. With MTT (methylthiazolyldiphenyl-tetrazolium-bromide) method, the effects of SSd and radiation on inhibiting SMMC-7721 cell growth were investigated. We also used transmission electron microscopy (TEM) to observe ultrastructural changes of cells. Colorimetry methods were used to measure content changes of glutathione (GSH) and malondialdehyde (MDA) in cells.
Results: Both SSd and radiation inhibited the growth of SMMC-7721 cells. The combination of SSd and radiotherapy had a time-dependent synergistic effect. Radiation caused ultrastructural damage to cells, and the damage was enhanced in combination with SSd. Radiation decreased the GSH content and increased the MDA content in cells, and this effect was suppressed after the intervention of SSd.
Conclusions: SSd can inhibit the growth of SMMC-7721 hepatoma cell lines in vitro. Additionally, it significantly enhances the effects of radiation on inhibiting the growth of SMMC-7721 hepatoma cell lines, and up-regulates the antioxidant level after the radiotherapy. Thus, SSd could be an ideal radiotherapy sensitizer for the treatment of liver cancer.

Keywords: Carcinoma, Hepatocellular - radiotherapy, Antineoplastic Agents - pharmacology, Cell Line, Tumor, Cell Proliferation - radiation effects, In Vitro Techniques, Liver Neoplasms - radiotherapy, Microscopy, Electron, Transmission, Oleanolic Acid - pharmacology, Radiation-Sensitizing Agents - pharmacology, Saponins - pharmacology, Tetrazolium Salts, Thiazoles