Effects of salidroside on glioma formation and growth inhibition together with improvement of tumor microenvironment.

OBJECTIVE To test the effects of salidroside on formation and growth of glioma together with tumor microenvironment. METHODS Salidroside extracted from Rhodiola rosea was purified and treated on human glioma cells U251 at the concentration of 20 µg/mL. 3-(4,5-dimethylthiazol-2-yl)-2,5-dephenyltetrazolium bromide (MTT) assay for cytotoxicity and flow cytometry (FCM) for cell cycle analysis were performed. Then for in vivo study, xenotransplantation tumor model in nude mice was generated and treated with salidroside at the concentration of 50 mg/kg(.)d for totally 20 d. Body weight and tumor size were detected every 2 d after the treatment. The levels of 8-isoprostane, superoxide dismutase (SOD) and malondialdehyde (MDA), special markers for oxidative stress, were detected while immunofluoresence staining was performed for astrocyte detection. RESULTS For in vitro study, salidroside could decrease the viability of human glioma cells U251 and the growth of U251 cells at G0/G1 checkpoint during the cell cycle. For in vivo study, salidroside could also inhibit the growth of human glioma tissue in nude mice. The body weight of these nude mice treated with salidroside did not decrease as quickly as control group. In the tumor xenotransplantation nude mice model, mice were found of inhibition of oxidative stress by detection of biomarkers. Furthermore, overgrowth of astrocytes due to the stimulation of oxidative stress in the cortex of brain was inhibited after the treatment of salidroside. CONCLUSIONS Salidroside could inhibit the formation and growth of glioma both in vivo and in vitro and improve the tumor microenvironment via inhibition of oxidative stress and astrocytes.