title: Role of ROS in the protective effect of silibinin on sodium nitroprusside-induced apoptosis in rat pheochromocytoma PC12 cells.
abstract: Silibinin mostly has been used as hepatoprotectants, but it has other interesting activities, e.g. anti-cancer, cardial protective and brain-protective activities. A previous study demonstrated that silibinin protected amyloid β (Aβ)-induced mouse cognitive disorder by behavioural pharmacological observation. This study assessed the effect of silibinin on sodium nitroprusside (SNP)-treated rat pheochromocytoma PC12 cells. Subsequent morphologic observation, flow cytometric analysis and Western blot analysis indicated that treatment with SNP significantly induced apoptosis in PC12 cells. However, silibinin eliminated the apoptotic effect by reactive oxygen species (ROS) generation, especially hydroxyl free radical. Silibinin-induced autophagy through ROS generation when exerting a protective effect and silibinin-induced autophagy also enhanced the ROS generation since 3-methyladenine (3-MA), a specific autophagy inhibitor, decreased the ROS generation and rapamycin, an autophagy inducer, enhanced the ROS generation. Therefore, there exists a positive feedback loop between autophagy and ROS generation. Autophagy prevented SNP-induced apoptosis, since the addition of 3-MA significantly eliminated the protective effect of silibinin. This protective effect was attributed to the generation of ROS and its two downstream Ras/PI3K/NF-κB and Ras/Raf/MEK/ERK pathways. Both prevented PC12 cells from apoptosis. The PI3K/NF-κB pathway induced autophagy to protect PC12 cells, but the Raf/MEK/ERK pathway directly protected PC12 cells bypassing the autophagic effect.
authors.affiliation: China-Japan Research Institute of Medical and Pharmaceutical Sciences, Shenyang Pharmaceutical University, Shenyang 110016, PR China.
authors.forename: Binbin
authors.initials: B
authors.lastname: Liu
authors.forename: Pengfei
authors.initials: P
authors.lastname: Yang
authors.forename: Yuanchao
authors.initials: Y
authors.lastname: Ye
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhou
authors.forename: Lingzhi
authors.initials: L
authors.lastname: Li
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Tashiro
authors.forename: Satoshi
authors.initials: S
authors.lastname: Onodera
authors.forename: Takashi
authors.initials: T
authors.lastname: Ikejima
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001343:Autophagy / Q000187:drug effects; D015153:Blotting, Western; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005434:Flow Cytometry; D048369:MAP Kinase Kinase 1 / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D009599:Nitroprusside / Q000494:pharmacology*; D015689:Oncogene Protein p21(ras) / Q000378:metabolism; D016716:PC12 Cells; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism*; D000077385:Silybin; D012838:Silymarin / Q000494:pharmacology*; D020123:Sirolimus / Q000494:pharmacology; D048490:raf Kinases / Q000378:metabolism
chemical_list: D016328:NF-kappa B; D017382:Reactive Oxygen Species; D012838:Silymarin; D009599:Nitroprusside; D000077385:Silybin; C025946:3-methyladenine; D019869:Phosphatidylinositol 3-Kinases; D048490:raf Kinases; D048049:Extracellular Signal-Regulated MAP Kinases; D048369:MAP Kinase Kinase 1; D015689:Oncogene Protein p21(ras); D000225:Adenine; D020123:Sirolimus