Related Experiment Video
Updated: Feb 14, 2026

Production and Detection of Reactive Oxygen Species ROS in Cancers
Published on: November 21, 2011
Reactive Oxygen Species Play a Biphasic Role in Brain Ischemia
Jiping Yang1, Jinchong Qi1, Baoxin Xiu1
1a Department of Medical Imaging , The Second Hospital of Hebei Medical University , Shijiazhuang , Hebei Province , China.
Objective:
Reactive oxygen species (ROS) are the essential mechanism involving in the ischemic process. Due to their complex characteristics, the precise effects of ROS on post-ischemic neurons remain uncertain. This study aimed to investigate the potential role of ROS in brain ischemia.
Methods:
Dynamic ROS levels in the perifocal cortex were evaluated after right middle cerebral artery occlusion (MCAO) of SD rats. Furthermore the role of ROS was assessed following delayed treatment with the ROS scavenger dimethylthiourea (DMTU) after brain ischemia.
Results:
ROS levels markedly increased at 1 hr after reperfusion and then gradually decreased as the post-reperfusion time interval increased. ROS levels reached their lowest point at 3 days after reperfusion before increasing and showing a second peak at 7 days after reperfusion. ROS levels negatively correlated with neurological function scores. Delayed DMTU treatment after stroke worsened neurological outcomes, decreased microvessel density and inhibited stress-activated protein kinase activation.
Conclusion:
ROS may play a biphasic role in cerebral ischemia. Namely, ROS may induce damage during the injury phase of brain ischemia and participate in improving neurological function during the recovery phase.
Related Concept Videos
Keystone Species
What is a Species?
Formation of Species
Social Foundations of Self I: Play and Game
Cross-reactivity
Reactivity of Enols

