title: Homocysteine Aggravates Cortical Neural Cell Injury through Neuronal Autophagy Overactivation following Rat Cerebral Ischemia-Reperfusion.
abstract: Elevated homocysteine (Hcy) levels have been reported to be involved in neurotoxicity after ischemic stroke. However, the underlying mechanisms remain incompletely understood to date. In the current study, we hypothesized that neuronal autophagy activation may be involved in the toxic effect of Hcy on cortical neurons following cerebral ischemia. Brain cell injury was determined by hematoxylin-eosin (HE) staining and TdT-mediated dUTP Nick-End Labeling (TUNEL) staining. The level and localization of autophagy were detected by transmission electron microscopy, western blot and immunofluorescence double labeling. The oxidative DNA damage was revealed by immunofluorescence of 8-Hydroxy-2'-deoxyguanosine (8-OHdG). Hcy treatment aggravated neuronal cell death, significantly increased the formation of autophagosomes and the expression of LC3B and Beclin-1 in the brain cortex after middle cerebral artery occlusion-reperfusion (MCAO). Immunofluorescence analysis of LC3B and Beclin-1 distribution indicated that their expression occurred mainly in neurons (NeuN-positive) and hardly in astrocytes (GFAP-positive). 8-OHdG expression was also increased in the ischemic cortex of Hcy-treated animals. Conversely, LC3B and Beclin-1 overexpression and autophagosome accumulation caused by Hcy were partially blocked by the autophagy inhibitor 3-methyladenine (3-MA). Hcy administration enhanced neuronal autophagy, which contributes to cell death following cerebral ischemia. The oxidative damage-mediated autophagy may be a molecular mechanism underlying neuronal cell toxicity of elevated Hcy level.
authors.affiliation: Department of Nutrition and Food Science, School of Public Health, Tianjin Medical University, Tianjin 30070, China. zyq0926@126.com.
authors.forename: Yaqian
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Department of Nutrition and Food Science, School of Public Health, Tianjin Medical University, Tianjin 30070, China. huangguowei@tmu.edu.cn.
authors.forename: Guowei
authors.initials: G
authors.lastname: Huang
authors.affiliation: Department of Nutrition and Food Science, School of Public Health, Tianjin Medical University, Tianjin 30070, China. chenshuang050109@126.com.
authors.forename: Shuang
authors.initials: S
authors.lastname: Chen
authors.affiliation: Department of Nutrition and Food Science, School of Public Health, Tianjin Medical University, Tianjin 30070, China. gou.yun1990@163.com.
authors.forename: Yun
authors.initials: Y
authors.lastname: Gou
authors.affiliation: Department of Nutrition and Food Science, School of Public Health, Tianjin Medical University, Tianjin 30070, China. dongjulia@163.com.
authors.forename: Zhiping
authors.initials: Z
authors.lastname: Dong
authors.affiliation: Department of Nutrition and Food Science, School of Public Health, Tianjin Medical University, Tianjin 30070, China. zhangxumei@tmu.edu.cn.
authors.forename: Xumei
authors.initials: X
authors.lastname: Zhang
mesh_terms: D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D001343:Autophagy / Q000187:drug effects*; D015153:Blotting, Western; D002545:Brain Ischemia / Q000503:physiopathology*; D002540:Cerebral Cortex / Q000293:injuries* / Q000378:metabolism / Q000473:pathology; D005455:Fluorescent Antibody Technique; D006710:Homocysteine / Q000633:toxicity*; D020244:Infarction, Middle Cerebral Artery; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000473:pathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury
chemical_list: D051017:Apoptosis Regulatory Proteins; D006710:Homocysteine
keywords: autophagy; homocysteine; neurons; oxidative stress; reperfusion injury