ABSTRACT
Objective: To investigate the induetion of apoptosis in human renal tubular epithelial HK-2 cells by emodin and whether endoplasmic reticulum (ER) stress is involved in its mechanism. Methods: HK-2 cells were cultured and treated with various concentration of emodin at different time points. The cell viability was determined by MTT assay. The gene expression of glucose-regulated protein 78 (GRP78), CCAAT/enhancer-binding protein-homologous protein (CHOP), activating transcription factor 3 (ATF3), and X-box binding protein 1 splicing (XBP1s) was evaluated by quantitative real-time PCR. The protein expression of caspase-3, GRP78, CHOP, and eukaryotic initiation factor 2 alpha (eIF2α) was detected by Western blotting. Results: The viability of HK-2 cells was decreased by emodin in a dose-dependent manner, and the apoptosis of the cells was associated with caspase-3 shear activation. The treatment with emodin in HK-2 cells caused the increase in eIF2α phosphorylation, XBP1 mRNA splicing, the gene expression of GRP78, CHOP, and ATF3, and the protein expression of GRP78 and CHOP. The pretreatment with 4-phenylbutyric acid and salubrinal significantly increased the viability of HK-2 cells, indicating the role of ER stress in emodin-induced apoptosis. Conclusion: Emodin induces the apoptosis in HK-2 cells and ER stress is involved in emodin-induced apoptosis.
ABSTRACT
The aim of this study is to investigate the protection effect of tanshinone IIA (Tan) against triptolide (TP)-induced liver injury and the mechanisms involved. Acute liver injury was induced by intraperitoneal injection of TP (1 mg x kg(-1)) in mice. The activities of AST, ALT and LDH in serum and the levels of GSH, GST, GSH-PX, SOD, CAT and MDA in liver tissue were detected. The histopathological changes of liver tissues were observed after HE staining. Nrf2 translocation in liver tissue was detected by Western blotting, and real-time PCR was used to measure the expression levels of GCLC, NQO1 and HO-1 mRNA. The results showed that pretreatment with Tan significantly prevented the TP induced liver injury as indicated by reducing the activities of AST, ALT and LDH (P < 0.01). Tan pretreatment also prevented TP-induced oxidative stress in the mice liver by inhibiting MDA and restoring the levels of GSH, GST, SOD and CAT (P < 0.05). Parallel to these changes, pretreatment with Tan could attenuate histopathologic changes induced by TP. Furthermore, the results indicated that Tan pretreatment caused nuclear accumulation of Nrf2 as well as induction of mRNA expression of antioxidant response element (ARE)-driven genes such as GCLC, NQO1 and HO-1. These results indicated that Tan could protect against TP-induced acute liver injury via the activation of Nrf2/ARE pathway.
Subject(s)
Animals , Male , Mice , Antioxidant Response Elements , Chemical and Drug Induced Liver Injury , Metabolism , Pathology , Diterpenes , Toxicity , Abietanes , Pharmacology , Drugs, Chinese Herbal , Pharmacology , Epoxy Compounds , Toxicity , Glutamate-Cysteine Ligase , Genetics , Metabolism , Heme Oxygenase-1 , Genetics , Metabolism , Liver , Metabolism , Pathology , Membrane Proteins , Genetics , Metabolism , Mice, Inbred C57BL , NAD(P)H Dehydrogenase (Quinone) , Genetics , Metabolism , NF-E2-Related Factor 2 , Metabolism , Phenanthrenes , Toxicity , RNA, Messenger , Metabolism , Signal TransductionABSTRACT
This study is to investigate the protection effect of schisandrin B (Sch B) against oxidation stress of HK-2 cells induced by cisplatin and the mechanisms involved. HK-2 cells were cultured and divided into different groups: solvent control group, cisplatin exposure group, positive group, Sch B treatment group. Cell viability and toxicity were evaluated by MTT and LDH assay. GSH level and SOD enzymes activities were also measured. DCFH-DA as fluorescence probe was used to detect ROS level by fluorescence microplate reader. Nrf2 translocation was detected by Western blotting. Real time Q-PCR was used to detect expressions of NQO1, HO-1 and GCLC mRNA level. The results showed that Sch B could significantly inhibit the decline of cell viability induced by cisplatin treatment (P < 0.05) and the protective effect was in a dose dependent manner. Furthermore, Sch B treatment significantly inhibited the increase of ROS level induced by cisplatin and reversed the decrease of GSH level (P < 0.05). When Sch B concentration was up to 5 micromol x L(-1), SOD enzyme activities were also enhanced significantly compared with that of the cisplatin group (P < 0.05). It was shown that Sch B could cause nuclear accumulation of Nrf2 in association with downstream activation of Nrf2 mediated oxidative response genes such as GCLC, NQO1 and HO-1. These results suggested Sch B could protect against the oxidative damage of HK-2 cells induced by cisplatin via the activation of Nrf2/ARE signal pathway.