Objective To investigate the relationship between the timing of diazoxide injected and its effect against brain damage after middle cerebral artery occlusion(MCAO) in male rats,and to establish a simple,sensitive,rapi...Objective To investigate the relationship between the timing of diazoxide injected and its effect against brain damage after middle cerebral artery occlusion(MCAO) in male rats,and to establish a simple,sensitive,rapid method of quantitative analysis.Methods 8 mmol/L diazoxide(6 μl) was injected into the lateral cerebral ventricle at the time of 30 min before ischemia,10 min,30 min,and 60 min during ischemia,and 10min during reperfusion,respectively.After reperfusion 22 hours,the tissue of hemisphere was incubated in 2,3,5-triphenyltetrazolium chloride(TTC) for 30 minutes,and then red formazan was extracted by solvent extraction and measured by Microplate Reader.Results Neurological score was improved 22 h later in the animals treated with diazoxide before ischemia and 10 min during ischemia compared with sham treatment(P<0.05).Spectrophotometric measurements of the extract showed diminished formazan coloration in all samples that was experienced ischemia-reperfusion injury compared to sham-operated controls.This apparent hemisphere injury was attenuated in the group of ischemia rats that received diazoxide at the time of 30 min before ischemia(0.28±0.06,P<0.01),10 min during ischemia(0.35±0.06,P<0.01),30 min during ischemia(0.41±0.09,P<0.01) compared to ischemia group without diazoxide administrated(0.52 ±0.06).Conclusion These finding suggest that opening of mitoKATP channels before ischemia and during early ischemia,but not that upon reperfusion,is important for enhancement of brain tolerance against infarction,and solvent extraction and microplate Reader quantitation of formazan has potential utility as an simple,objective way to index experimental brain injury.展开更多
文摘Objective To investigate the relationship between the timing of diazoxide injected and its effect against brain damage after middle cerebral artery occlusion(MCAO) in male rats,and to establish a simple,sensitive,rapid method of quantitative analysis.Methods 8 mmol/L diazoxide(6 μl) was injected into the lateral cerebral ventricle at the time of 30 min before ischemia,10 min,30 min,and 60 min during ischemia,and 10min during reperfusion,respectively.After reperfusion 22 hours,the tissue of hemisphere was incubated in 2,3,5-triphenyltetrazolium chloride(TTC) for 30 minutes,and then red formazan was extracted by solvent extraction and measured by Microplate Reader.Results Neurological score was improved 22 h later in the animals treated with diazoxide before ischemia and 10 min during ischemia compared with sham treatment(P<0.05).Spectrophotometric measurements of the extract showed diminished formazan coloration in all samples that was experienced ischemia-reperfusion injury compared to sham-operated controls.This apparent hemisphere injury was attenuated in the group of ischemia rats that received diazoxide at the time of 30 min before ischemia(0.28±0.06,P<0.01),10 min during ischemia(0.35±0.06,P<0.01),30 min during ischemia(0.41±0.09,P<0.01) compared to ischemia group without diazoxide administrated(0.52 ±0.06).Conclusion These finding suggest that opening of mitoKATP channels before ischemia and during early ischemia,but not that upon reperfusion,is important for enhancement of brain tolerance against infarction,and solvent extraction and microplate Reader quantitation of formazan has potential utility as an simple,objective way to index experimental brain injury.
