Heme oxygenase protects hippocampal neurons from ethanol-induced neurotoxicity.
Ethanol has deleterious effects on neuronal cells both in vivo and in vitro, but the mechanisms are unknown. Here, treatment with increasing doses of ethanol (from 20 up to 600mM) decreased the viability of a mouse hippocampal neuroblastoma cell line, HT22. The glutathione concentration decreased and intracellular reactive oxygen species (ROS) increased in a dose-and time-dependent manner, suggesting that the neurotoxicity was due to oxidative stress. Expression of heme oxygenase (HO)-1, a redox regulator and heat shock protein, increased with time after ethanol treatment, but HO-2 was expressed constitutively. The addition of 5microM zinc protoporphyrin IX (ZnPP IX), a competitive HO inhibitor, with the ethanol further reduced cell viability and increased intracellular ROS, but these effects were reversed by co-treatment with 50nM bilirubin, a well-known antioxidant and a product of HO catalysis. These results suggest that HO has a protective role in hippocampal neurons as an intrinsic factor against ethanol-induced oxidative stress and the protection depends on the degree of oxidative stress.
Ku
Bo Mi
BM
Department of Anatomy and Neurobiology, Institute of Health Sciences, College of Medicine, Gyeongsang National University, 92 Chilam-dong, Jinju, Gyeongnam, 660-751, Korea.
Joo
Yeon
Y
Mun
Jihye
J
Roh
Gu Seub
GS
Kang
Sang Soo
SS
Cho
Gyeong Jae
GJ
Choi
Wan Sung
WS
Kim
Hyun Joon
HJ
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D001663:Bilirubin / Q000494:pharmacology; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D002492:Central Nervous System Depressants / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000494:pharmacology; D000431:Ethanol / Q000633:toxicity*; D005786:Gene Expression Regulation / Q000187:drug effects; D005978:Glutathione / Q000378:metabolism; D006419:Heme Oxygenase (Decyclizing) / Q000502:physiology*; D006624:Hippocampus / Q000473:pathology*; D051379:Mice; D009447:Neuroblastoma; D009474:Neurons / Q000187:drug effects*; D011524:Protoporphyrins / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D013997:Time Factors
D000975:Antioxidants; D002492:Central Nervous System Depressants; D004791:Enzyme Inhibitors; D011524:Protoporphyrins; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; C017803:zinc protoporphyrin; D000431:Ethanol; D006419:Heme Oxygenase (Decyclizing); D005978:Glutathione; D001663:Bilirubin