title: Baicalein protects human melanocytes from H₂O₂-induced apoptosis via inhibiting mitochondria-dependent caspase activation and the p38 MAPK pathway.
abstract: The removal of H(2)O(2) by antioxidants has been proven to be beneficial to patients with vitiligo. Baicalein (5,6,7-trihydroxyflavone; BE) has antioxidant activity and has been used in vitiligo therapy in Chinese traditional medicine. In this study, we investigated the potential protective effect and mechanisms of BE against H(2)O(2)-induced apoptosis in human melanocytes. Melanocytes from the PIG1 cell line were pretreated with different concentrations of BE for 1 h, followed by exposure to 1.0 mM H(2)O(2) for 24 h. Cell apoptosis, reactive oxygen species levels, and mitochondrial membrane potentials were evaluated by flow cytometry, and cell viability was determined by an MTT assay. The expressions of Bax, Bcl-2, caspase-3, total and phosphorylated ERKs, and p38 MAPK were assayed by Western blot to investigate the possible molecular mechanisms. Our results showed that BE significantly inhibited H(2)O(2)-induced apoptosis, intracellular reactive oxygen species generation, and changes in the mitochondrial membrane potential. It also reduced the Bax/Bcl-2 ratio, the release of cytochrome c, the activation of caspase-3, and the phosphorylation of p38 MAPK in a concentration-dependent manner. The results demonstrate for the first time that BE exerts a cytoprotective role in H(2)O(2)-induced apoptosis by inhibiting the mitochondria-dependent caspase activation and p38 MAPK pathway.
authors.affiliation: Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China 710032.
authors.forename: Bangmin
authors.initials: B
authors.lastname: Liu
authors.forename: Zhe
authors.initials: Z
authors.lastname: Jian
authors.forename: Qiang
authors.initials: Q
authors.lastname: Li
authors.forename: Kai
authors.initials: K
authors.lastname: Li
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Wang
authors.forename: Ling
authors.initials: L
authors.lastname: Liu
authors.forename: Lingzhen
authors.initials: L
authors.lastname: Tang
authors.forename: Xiuli
authors.initials: X
authors.lastname: Yi
authors.forename: Hua
authors.initials: H
authors.lastname: Wang
authors.forename: Chunying
authors.initials: C
authors.lastname: Li
authors.forename: Tianwen
authors.initials: T
authors.lastname: Gao
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3 / Q000235:genetics / Q000378:metabolism; D061945:Caspase Inhibitors; D002470:Cell Survival; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D005260:Female; D044950:Flavanones / Q000494:pharmacology*; D005434:Flow Cytometry; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D020935:MAP Kinase Signaling System / Q000187:drug effects; D008544:Melanocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000037:antagonists & inhibitors; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism
chemical_list: D000975:Antioxidants; D061945:Caspase Inhibitors; D044950:Flavanones; D017382:Reactive Oxygen Species; C006680:baicalein; D006861:Hydrogen Peroxide; D048051:p38 Mitogen-Activated Protein Kinases; D053148:Caspase 3