Targeting X? Factor Traced Fibrin Deposition And No-reflow Of Microcirculation After Thrombolysis In Ischemic Stroke

Part One Neurological Recovery after Thrombolytic Therapy in Acute Ischemic Stroke MiceObjective To observe the recanalization of MCAO after thrombolytic therapy of acute ischemic stroke mice by 7.0T MRI after thrombolysis.Methods 70 C57BL/6J mice were divided into sham group(n=6),model group(n=15)and thrombolytic group(n=49).The models of focal cerebral ischemia(middle cerebral artery occlusion)was induced via photothrombosis,the Magnetic resonance angiography(MRA)and apparent diffusion coefficient(ADC)of the magnetic resonance were used for successful modeling.Acquisition of Diffusion-weighted imaging(DWI),ADC,3-dimensional fast low angle shot(3D-Flash)and T2 signal by Magnetic resonance(MRI).ADC and 3D-Flash images handled by Paravision5.0 software in workstation.The infarct area of T2 was outlined by the Image J.Results The rate of the middle cerebral artery occlusion were recanalized is about 61.2%,nonthrombotic mice obstruction of the middle cerebral artery recanalized rate is about 6.67%,respectively.The ADC score of ipsilateral cerebrum(0.62±0.13)×0.001mm2/sec of the model mice was lower than that of the contralateral ADC(0.43±0.07)×0.001mm2/sec,respectively.The infarct size(10.52±4.41)mm2 in the thrombolytic therapy group was significantly smaller than that in the untreated mice(23.38±1.66)mm2,respectively.The fast-moving test of the balance beam,The speed of sham mice group(30.97±7.32)×0.01m/s was significantly faster than that of thrombolytic mice(15.39±8.82)×0.01m/s and mice without thrombolytic therapy(2.56±2.80)×0.01m/s,respectively.The modified neurological deficits scores(m NSS)of sham group(0.5±0.54)was significantly lower than that of thrombolytic mice(4.87±2.34)and non-thrombolytic mice(9.83±1.59),respectively.The weight of sham group increased continuously,and the weight of model group and thrombolytic group decreased firstly and then increased.Condusion The model of recanalization of MCAO after thrombolysis for ischemic stroke was successfully established,but the recovery of neurological function is significantly stronger than nonthrombolytic group.Part Two Tracing Fibrin and “no-reflow” of Microcirculation after thrombolysis in ischemic strokeObjective: To investigated the relationship between fibrin deposition and “no-reflow” of microcirculation after thrombolysis in acute ischemic stroke.Methods: The models of focal cerebral ischemia(middle cerebral artery occlusion)was induced via photothrombosis,recanalization of MCAO after thrombolytic therapy by rt PA.The targeting FXIIIa peptide connected with Cy7 was built to be a near infrared fluorescent(NIRF)probe.24 h later,after rt PA thrombolysis fibrin deposition was detected by NIRF.At the same time,the opening of the middle cerebral artery was observed by 3D-FLASH.The size of the lesion was observed by T2 WI,and the accumulation of red blood cells and fibrin deposition were observed by pathological sections(Hematoxylin and Eosin staining and immunohistochemistry).Results: The NIRF showed that the fluorescence intensity of the ipsilateral side of the model group and thrombolytic group was significantly higher than that of the contralateral side.But the thrombolytic group were compared with the model group,there was no significant difference in the intensity of the ipsilateral side(TBRs: contralateral(0.566±0.066)and ipsilateral(1.102±0.061)of thrombolytic group;contralateral(0.589±0.038)and ipsilateral(1.157±0.044)of model group(The unit of TRBs(p/s/cm2/sr)/(?W/cm2)×108),respectively).3D-FLASH showed that the opening rate of the middle cerebral artery in the mice was about 58.33% after thrombolytic therapy and the opening rate of the model group was about 22.22%,respectively.The results of T2 WI showed that the infarct area of the thrombolytic group was significantly smaller than that in the model group(nonthrombolytic therapy(23.39±1.58)mm2 and the thrombolytic therapy(7.40±1.46)mm2,respectively).In the thrombolytic group,there were a large number of red blood cells(RBCs)accumulated in the lesion area and marginal capillary,and there were obvious fibrin deposition in and around capillaries.Conclusion: Recanalization of MCAO after thrombolysis by rt PA was successfully built,but the microcirculation obstruction still exists in and aroud the lesion area after thrombolysis.The deposition of fibrin in the capillary is one of the reasons of the local disorder and the formation of "no reflow" of microcirculation.