Protective effects of quercetin on hepatic cell damage induced by oxidative stress / 天津医药

Objective To explore the protective effects of quercetin on damage induced by oxidative stress and to clari?fy its molecular mechanism. Methods Chang liver cell cultures were randomly divided into control groups, H2O2 group and 3 doses of quercetin groups. Cell survival rate was detected with MTT. Cell apoptotic rate was measured by FACS(Fluores?cence-activated cell sorting). Intracellular reactive oxygen species (ROS) level in Chang liver cells were tested by flow cy?tometer. The DCF fluorescence intensity of DCFH-DA-stained intracellular ROS was observed by fluorescence microscope. The levels of malondialdehyde (MDA), superoxide dismutase(SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) were determined in liver cells using commercial available kits. The expression of Nrf2 were detected by Western blot. Re?sults Compared with control, cell survival rate and levels of SOD, CAT and GSH-Px decreased significantly in H2O2 group (P < 0.05 ),while cell appotosis rate, content of MDA and mean fluorescence intensity(MFI) increased in H2O2 group (P <0.05). In comparison with H2O2, expression of Nrf2 protein was higher in all three quercetin treatment groups (P<0.05). Con?clusion Quercetin protected Chang liver cells from H2O2-induced oxidative stress, which may be caused by the increased ex?pressions of down stream antioxidant genes via activating the Nrf2-ARE signaling pathway.

Evaluation of Oxidative DNA Damage Using an Alkaline Single Cell Gel Electrophoresis (SCGE) Comet Assay, and the Protective Effects of N-Acetylcysteine Amide on Zearalenone-induced Cytotoxicity in Chang Liver Cells

Zearalenone (ZEN) is a non-steroidal estrogenic mycotoxin produced by several species of Fusarium that are found in cereals and agricultural products. ZEN has been implicated in mycotoxicosis in farm animals and in humans. The toxic effects of ZEN are well known, but the ability of an alkaline Comet assay to assess ZEN-induced oxidative DNA damage in Chang liver cells has not been established. The first aim of this study was to evaluate the Comet assay for the determination of cytotoxicity and extent of DNA damage induced by ZEN toxin, and the second aim was to investigate the ability of N-acetylcysteine amide (NACA) to protect cells from ZEN-induced toxicity. In the Comet assay, DNA damage was assessed by quantifying the tail extent moment (TEM; arbitrary unit) and tail length (TL; arbitrary unit), which are used as indicators of DNA strand breaks in SCGE. The cytotoxic effects of ZEN in Chang liver cells were mediated by inhibition of cell proliferation and induction of oxidative DNA damage. Increasing the concentration of ZEN increased the extent of DNA damage. The extent of DNA migration, and percentage of cells with tails were significantly increased in a concentration-dependent manner following treatment with ZEN toxin (p < 0.05). Treatment with a low concentration of ZEN toxin (25 microM) induced a relatively low level of DNA damage, compared to treatment of cells with a high concentration of ZEN toxin (250 microM). Oxidative DNA damage appeared to be a key determinant of ZEN-induced toxicity in Chang liver cells. Significant reductions in cytolethality and oxidative DNA damage were observed when cells were pretreated with NACA prior to exposure to any concentration of ZEN. Our data suggest that ZEN induces DNA damage in Chang liver cells, and that the antioxidant activity of NACA may contribute to the reduction of ZEN-induced DNA damage and cytotoxicity via elimination of oxidative stress.

Active effect of hemeoxygenase-1 expression on Chang liver cell induced by inorganic arsenic / 中国地方病学杂志

Objective To observe whether sodium arsenite(NaAsO2)can activate the expressions of hemeoxygenase-1(HO-1)of normal human liver cell line named Chang liver.Methods Chang liver cells were exposed to NaAsO2 at 10 μmoL/L,0(contml),2,6,12,24 h and at 0(control),5,10,25,50 μmol/L in 12 h, followed by the measuring of the expressions of HO-1 protein in ceUs with western blot.Results In 10 μmol/L groups Chang liver cells exposed for 6,12,24 h cultured in vitro,the expressions of HO-l protein(3.97±0.72, 12.92±2.98,23.29±3.82)was significantly higher than that of control(1.00±0.00),and compared with the control, the difference being statistically significant(F=85.83,P＜0.01;t=-9.42,-8.95,-13.83,respectively,P＜ 0.05 or＜0.01).In 12 h,5,10,25 and 50 μmol/L groups cultured in vitro,the expressions of HO-1(16.34±0.25, 7.75±0.39,7.93±0.14,12.48±0.35)was significantly higher than that of control(1.00±0.00).and compared with the control,the difference being statistically significant(F=85.83,P＜0.01;t=-36.25,-30.19,-86.40, -56.40,respectively,all P＜0.01).Conclusion Inorganic arsenic call induce the activation of HO-1,promote the expression of protein in a time-and dose-dependent manner.

Involvement of ROS and JNK1 in selenite-induced a poptosisin Chang liver cells

Selenium is a dietary essential trace nutrient with important biological roles. Selenocompounds were reported to induce apoptosis in many types of tumor cells. In this study, we investigated the signaling pathway involved in the selenite-induced apoptosis using Chang liver cells as a non-malignant cell model. The Chang liver cell apoptosis induced by selenite (10 mM) was confirmed by DNA fragmentation and typical apoptotic nuclear changes. Treatment of selenite increased intracellular reactive oxygen species (ROS) level and c-Jun N-terminal kinase1 (JNK1) phosphorylation. The selenite-induced cell death was attenuated by SP600125, a specific inhibitor of JNK, and by dominant negative JNK1 (DN-JNK1). Antioxidants such as glutathione (GSH), N-acetyl cysteine (NAC), curcumin, epigallocatechin gallate (EGCG) and epicatechin (EC) inhibited selenite-induced intracellular ROS elevation and JNK1 phosphorylation. Our results suggest that selenite-induced apoptosis in Chang liver cells was preceded by the ROS generation and JNK1 activation.