title: Repetitive/temporal hypoxia increased P-glycoprotein expression in cultured rat brain microvascular endothelial cells in vitro.
abstract: The aim of the study was to investigate whether repetitive/temporal hypoxia up-regulated P-glycoprotein (P-gp) in cultured rat brain microvascular endothelial cells (rBMECs). Cultured rBMECs were used as in vitro blood brain barrier (BBB) model. Cells reached confluence were subjected to temporal hypoxic exposure. Under free-glucose cultured medium, the cells were covered by sterile paraffin oil for 15 min, inducing temporal hypoxic exposure. The hypoxic-exposure was carried out once every day up to 8 days, leading to the repetitive/temporal hypoxia in rBMECs. The cell viability was tested using CCK-8 kit, function and levels of P-gp in the cells were measured using rhodamine 123 uptake and western blot, respectively. It was found that 8-temporal hypoxic exposure induced 1.6-fold increase of P-gp level in cells, accompanied by decrease of cellular accumulation of rhodamine 123. Cellular accumulation of phenobarbital was also decreased. These findings indicated that repetitive/temporal hypoxia may be one of the factors resulting in P-gp overexpression in refractory epilepsy.
authors.affiliation: Key Lab of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China. xdliu@cpu.edu.cn
authors.forename: Liu
authors.initials: L
authors.lastname: Xiao-Dong
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhi-Hong
authors.forename: Yang
authors.initials: Y
authors.lastname: Hui-Wen
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D001692:Biological Transport / Q000187:drug effects / Q000502:physiology; D001921:Brain / Q000033:anatomy & histology; D002470:Cell Survival; D002478:Cells, Cultured; D016572:Cyclosporine / Q000494:pharmacology; D042783:Endothelial Cells / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000166:cytology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000502:physiology*; D000860:Hypoxia / Q000473:pathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020112:Rhodamine 123 / Q000378:metabolism; D012844:Sincalide / Q000378:metabolism; D013997:Time Factors
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D004791:Enzyme Inhibitors; D020112:Rhodamine 123; D016572:Cyclosporine; D012844:Sincalide