title: Baicalein-induced apoptosis via endoplasmic reticulum stress through elevations of reactive oxygen species and mitochondria dependent pathway in mouse-rat hybrid retina ganglion cells (N18).
abstract: Studies were designed to investigate the effects of baicalein on mouse-rat hybrid retina ganglion cells (N18) to better understand its effect on apoptosis and apoptosis-related genes in vitro. Cell viability, reactive oxygen species (ROS), cytoplasmic Ca2+, mitochondrial membrane potential (MMP), apoptosis induction, and caspases-3 activity were examined by flow cytometric assay. Apoptosis-associated proteins such as p53, Bax, Bcl-2, cytochrome c, and caspase-3 were examined by Western blot. We demonstrated the increase in the levels of p53, Bax, and cytochrome c and decrease in the level of Bcl-2, which are associated with the induction of apoptotic cell death after 24 h treatment with baicalein in N18 cells. Baicalein induced an increase in the cytoplasmic levels of ROS and Ca2+ in 1 h and reached their peak at 3 h, and thereafter a loss of MMP by flow cytometry. We also demonstrated a release of the cytochrome c from mitochondria into cytosol and an activation of caspase-3, which led to the occurrence of apoptosis in N18 cells treated with baicalein by Western blot. Pretreatment was conducted with BAPTA (intracellular calcium chelator) in baicalein-treated cells, the decline of MMP was recovered, and the increase in the level of cytoplasmic Ca2+ was suppressed, and the proportion of apoptosis was also markedly diminished. In conclusion, our data suggests that oxidative stress and cellular Ca2+ modulates the baicalein-induced cell death via a Ca2+-dependent mitochondrial death pathway in N18 cells.
authors.affiliation: Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan, ROC.
authors.forename: Yu-Ching
authors.initials: YC
authors.lastname: Li
authors.forename: Hui-Ju
authors.initials: HJ
authors.lastname: Lin
authors.forename: Jen-Hung
authors.initials: JH
authors.lastname: Yang
authors.forename: Jai-Sing
authors.initials: JS
authors.lastname: Yang
authors.forename: Heng-Chien
authors.initials: HC
authors.lastname: Ho
authors.forename: Shu-Jen
authors.initials: SJ
authors.lastname: Chang
authors.forename: Te-Chun
authors.initials: TC
authors.lastname: Hsai
authors.forename: Hsu-Feng
authors.initials: HF
authors.lastname: Lu
authors.forename: An-Cheng
authors.initials: AC
authors.lastname: Huang
authors.forename: Jing-Gung
authors.initials: JG
authors.lastname: Chung
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D017209:Apoptosis; D002460:Cell Line; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D044950:Flavanones / Q000494:pharmacology*; D006822:Hybrid Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D008928:Mitochondria / Q000502:physiology*; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012165:Retinal Ganglion Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D044950:Flavanones; D017382:Reactive Oxygen Species; C006680:baicalein