title: Baicalin ameliorates H2O2 induced cytotoxicity in HK-2 cells through the inhibition of ER stress and the activation of Nrf2 signaling.
abstract: Renal ischemia-reperfusion injury plays a key role in renal transplantation and greatly affects the outcome of allograft. Our previous study proved that Baicalin, a flavonoid glycoside isolated from Scutellaria baicalensis, protects kidney from ischemia-reperfusion injury. This study aimed to study the underlying mechanism in vitro. Human renal proximal tubular epithelial cell line HK-2 cells were stimulated by H2O2 with and without Baicalin pretreatment. The cell viability, apoptosis and oxidative stress level were measured. The expression of endoplasmic reticulum (ER) stress hallmarks, such as binding immunoglobulin protein (BiP) and C/EBP homologous protein (CHOP), were analyzed by western blot and real-time PCR. NF-E2-related factor 2 (Nrf2) expression was also measured. In the H2O2 group, cell viability decreased and cell apoptosis increased. Reactive Oxygen Species (ROS) and Glutathione/Oxidized Glutathione (GSH/GSSG) analysis revealed increased oxidative stress. ER stress and Nrf2 signaling also increased. Baicalin pretreatment ameliorated H2O2-induced cytotoxicity, reduced oxidative stress and ER stress and further activated the anti-oxidative Nrf2 signaling pathway. The inducer of ER stress and the inhibitor of Nrf2 abrogated the protective effects, while the inhibitor of ER stress and the inducer of Nrf2 did not improve the outcome. This study revealed that Baicalin pretreatment serves a protective role against H2O2-induced cytotoxicity in HK-2 cells, where the inhibition of ER stress and the activation of downstream Nrf2 signaling are involved.
authors.affiliation: Department of Urology, Fudan University Zhongshan Hospital, Shanghai 20032, China. linmiao@fudan.edu.cn.
authors.forename: Miao
authors.initials: M
authors.lastname: Lin
authors.affiliation: Shanghai Key Laboratory of Organ Transplantation, Shanghai 20032, China. ljlmjw@gmail.com.
authors.forename: Long
authors.initials: L
authors.lastname: Li
authors.affiliation: Shanghai Key Laboratory of Organ Transplantation, Shanghai 20032, China. yzhang_med@fudan.edu.cn.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Shanghai Key Laboratory of Organ Transplantation, Shanghai 20032, China. longzheng0814@126.com.
authors.forename: Long
authors.initials: L
authors.lastname: Zheng
authors.affiliation: Department of Urology, Fudan University Zhongshan Hospital, Shanghai 20032, China. xu.ming@zs-hospital.sh.cn.
authors.forename: Ming
authors.initials: M
authors.lastname: Xu
authors.affiliation: Department of Urology, Fudan University Zhongshan Hospital, Shanghai 20032, China. rong.ruiming@zs-hospital.sh.cn.
authors.forename: Ruiming
authors.initials: R
authors.lastname: Rong
authors.affiliation: Shanghai Key Laboratory of Organ Transplantation, Shanghai 20032, China. tyzhu_dr@163.com.
authors.forename: Tongyu
authors.initials: T
authors.lastname: Zhu
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D002460:Cell Line; D059865:Endoplasmic Reticulum Stress; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D005419:Flavonoids / Q000494:pharmacology*; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity; D051267:NF-E2-Related Factor 2 / Q000235:genetics / Q000378:metabolism*; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D000975:Antioxidants; D005419:Flavonoids; D051267:NF-E2-Related Factor 2; C495635:NFE2L2 protein, human; D017382:Reactive Oxygen Species; C038044:baicalin; D006861:Hydrogen Peroxide