ABSTRACT
Objective: To explore the effects of plumbagin (PLB) on the proliferation and apoptosis of hepatocellular carcinoma hepG2R cells resistant to sorafenib, and to clarify its mechanism. Methods: The hepatocellular carcinoma cells hepG2 were cultured in vitro and the models of sorafenib-resistant HepG2R cells were set up. MTT assay was used to identify the resistance factor and screen the concentration and time of drug. According to the results, the concentrations of sorafenib and PLB were confirmed as 5 μmol · L-1 and 2 μmol · L-1. The action time in various groups was 48 h. The HepG2R cells were randomly divided into control group, sorafenib (5 μmol · L-1) group, PLB (2 μmol · L-1) group, sorafenib (5 μmol · L-1) combined PLB (2 μmol · L-1) group (combination group). MTT assay was used to detect the cell vitality in various groups. The clone formation rates of cells in various groups were detected by clone formation assay. The apoptotic rates of cells in various groups were determined with Hoechst33342 assay and flow cytometry (FCM). The expression levels of cleaved Caspase-3, Bax and Bel-2 proteins in the cells in various groups were examined by Western blotting method, and the Bax/Bcl-2 ratio was calculated. The reactive oxygen (ROS) levels in the cells in various groups were detected by ROS detector kit. Results: As the increasing of concentrations of sorafenib, the cell vitalities of HepG2 and HepG2R cells were gradually decreased; the IC5o of sorafenib-resistant HepG2R cells was 4. 5 times as much as HepG2 cells (P<0. 05). The sensitivities of sorafenib resistant HepG2R cells were increased with the increasing of PLB concentrations and prolongation of time. Compared with control group, sorafenib group and PLB group, the clone formation rate of the cells in combination group was decreased (P<0. 05 or P<0. 01). The Hoechst 33342 assay results showed the nuclei were lightly stained; a few of the nuclei in sorafenib group and PLB group were strongly stained and bright; while in combination group, the nuclei were mostly stained and chromatin was condensed and bright. The FCM results showed that compared with control group, sorafenib group and PLB group, the apoptotic rate of cells in combination group was significantly increased (P< 0. 05 or P< 0. 01). The Western blotting results showed that the expression level of cleaved Caspase-3 in the cells and the Bax/Bcl -2 ratio in combination group were increased significantly (P<0. 05 or P<0. 01). The ROS level in the cells in combination group was higher than those in the other groups (P< 0.05 or P<0. 01). Conclusion: PLB can improve the resistance of hepartocellular carcinoma to sorafenib and the mechanism may be related to increasing the ROS level.
ABSTRACT
Objective To study the factors effect on the measurement of CT value.Methods CT water phantom was scanned using the regular condition of scaning first,then changed one of scaning conditions (thick slice, exposure capacity, reconstruction of function, kV, FOV and CT-scanner) to scan the water phantom again. The CT value (mean?SD) of image region of interest (ROI) was compared in two conditions. Results The mean CT value in the opposite ROI in thick slice 5mm and exposure capacity 150 mAs was similar to that in thick slice 10mm and exposure capacity 300mAs, the reconstruction of function Fc80 was lower Fc10 , the 130kV was distinct higher 120Kv in mean of CT value respectively.The SD(noise) in thick slice 5mm was near to the exposure capacity 150mAs, while in contrast to the thick slice 10mm and the exposure capacity 300mAs was obvious increased , but the reconstruction of function Fc80 was distinct higher Fc10, the 130kV was slightly lower 120Kv in SD(noise) respectively . All of mean CT value and the noise in the small field were higher in the middle field ,when CT imaging in the water phantom of the single small field .This result was also received when the old Toshiba CT-scanner was compared with the new GE CT-scanner in the differ water plantom.Conclusion The CT value is not constant and can’t act as a diagnostic standred.