Modified Rat Model Of Thromboembolic Stroke And The Effect Of Edaravone On The Inflammasome NLRP3 And Blood Brain Barrier-associated Protein After Embolic Stroke In Rat

Part ? Modified rat model of thromboembolic strokeObjective Thromboembolic Middle Cerebral Artery Occlusion(MCAO)model was optimized in this study by using different numbers and length of sections of thrombi to obtain appropriate brain and neurological injury,low mortality rate and high successful modeling rate.Materials and methods Fresh femoral artery blood was drawn to produce thrombi in vitro.The thromboembolic MCAO model was established through external carotid artery retrograde cannulation and small blood thrombi were injected into internal carotid artery.According to the number and length of thrombi injected into MCA,143 Sprague-Dawley rats were randomly divided into 7 groups:12*1.5 mm group(n=20),10*1.5 mm group(n=21),8*1.5 mm group(n=21),6*1.5 mm group(n=20),4*1.5 mm group(n=16),12*1.0 mm group(n=25)and 8*1.0 mm group(n=20).The rat brain infarct volume,neurological function deficits,brain swelling volume,together with the successful modeling rate and mortality rate,were assessed post 24 h embolization.8 sections of thrombi at 1.5 mm length was chosen to induce thromboembolic stroke and received intravenous rtPA at 4h after thrombi injected.Hemorrhage volumes were assessed by using spectrophotometric hemoglobin assay.Results Successful modeling rate,mortality and brain injury decreased along with the number of thrombi reduced.Rats with 8 sections of thrombi at 1.5 mm length had lower mortality rate(27.78%vs 63.16%,P<0.05),neurological deficit score(6.466±2.02 vs 9.14±3.39,P<0.05)and infarct volume(27.39±8.85%vs 39.94±10.25%,P<0.05)compared with those with 12 sections of thrombi at 1.5mm length.While no difference was found on successful modeling rate(85.7%vs 95%,P>0.05)between two groups.In addition,no significant difference was found on successful modeling rate,mortality or brain injury by decreasing the length of thrombi from 1.5 mm to 1.0 mm,no matter with 12 or 8 sections of thrombi(P>0.05).Hemorrhage volume of 8*1.5mm+rtPA group was significantly higher than cerebral embolism group(13.41±3.20 ?l vs 2.10±1.95 ?l,P<0.05).Conclusion Injection of 8 sections of thrombi at 1.5 mm length was the best point with a high successful stroke modeling rate,but a low mortality rate and is suitable for the study of hemorrhagic transformation in stroke after intravenous thrombolysis.Part ? The effect of edaravone on the inflammasome NLRP3 and blood brain barrier associated protein after embolic stroke in ratObjective To study the neuroprotective effects of edaravone on inflammasome NLRP3 and associated protein of the blood-brain barrier against cerebral ischemia injury.Materials and methods 60 male Sprague-Dawley rats were randomly divided into sham group,cerebral embolism group and edaravone group,respectively.Rat thromboembolic MCAO models were established and edaravone(3mg/kg)was intravenous injected immediately after occlusion and 4 hours after occlusion.At 24 hours after thrombi injected,mNSS score was used to evaluate neurological function defieits.Brain infarct volume was estimated by TTC staining.The expression of inflammasome NLRP3,occludin and ZO-1 was detected by Western blot.Immunohistochemistry was used to measure IgG leakage.Results The mNSS score and infarct volume of cerebral embolism group at 24 hours after stroke were significantly higher than sham group(P<0.01),but the mNSS score(6.50±1.35 vs 4.50±2.12,P<0.05)and infarct volume(29.99±7.56 vs 19.29±11.92,P<0.05)decreased when treated with edaravone.Edaravone treatment significantly attenuated inflammasome NLRP3 expression in cerebral ischemic area,degradation of BBB components(occludin,ZO-1)and IgG leakage.Conclusion Inflammasome NLRP3 play an important role in acute cerebral ischemia injury.Edaravone may provide neuroprotection by inhibiting expression of inflammasome NLRP3 and degradation of associated protein of blood brain barrier.