Some in vitro experiments have shown that erythropoietin （EPO） increases resistance to apoptosis and facilitates neuronal survival follow- ing cerebral ischemia. However, results from in vivo studies are rarely repo...Some in vitro experiments have shown that erythropoietin （EPO） increases resistance to apoptosis and facilitates neuronal survival follow- ing cerebral ischemia. However, results from in vivo studies are rarely reported. Perfusion-weighted imaging （PWI） and diffusion-weighted imaging （DWI） have been applied successfully to distinguish acute cerebral ischemic necrosis and penumbra in living animals; therefore, we hypothesized that PWI and DWI could be used to provide imaging evidence in vivo for the conclusion that EPO could reduce apoptosis in brain areas injured by cerebral ischemia/reperfusion. To validate this hypothesis, we established a rat model of focal cerebral ischemia/ reperfusion injury, and treated with intra-cerebroventricular injection of EPO （5,000 U/kg） 20 minutes before injury. Brain tissue in the ischemic injury zone was sampled using MRI-guided localization. The relative area of abnormal tissue, changes in PWI and DWI in the ischemic injury zone, and the number of apoptotic cells based on TdT-mediated dUTP-biotin nick end-labeling （TUNEL） were assessed. Our findings demonstrate that EPO reduces the relative area of abnormally high signal in PWI and DWI, increases cerebral blood volume, and decreases the number of apoptotic cells positive for TUNEL in the area injured by cerebral ischemia/reperfusion. The experiment pro- vides imaging evidence in vivo for EPO treating cerebral ischemia/reperfusion injury.展开更多
AIM： To investigate dynamical and image pathological characteristics of the liver on magnetic resonance （MR） diffusion-weighted imaging （DWI） in the rabbit VX-2 tumor model. METHODS： Forty New Zealand rabbits we...AIM： To investigate dynamical and image pathological characteristics of the liver on magnetic resonance （MR） diffusion-weighted imaging （DWI） in the rabbit VX-2 tumor model. METHODS： Forty New Zealand rabbits were included in the study and VX-2 tumor piece was implanted intrahepatically. Fifteen animals received two intrahepatic implantations while 25 had one intrahepatical implantation. DWI, T1- and T2-weighted of magnetic resonance imaging （MRI） were carried out on the 7th and the 14th d after implantation and DWI was conducted, respectively on the 21th d. Ten VX-2 tumor samples were studied pathologically. RESULTS： The rate of lump detected by DWI, TlWI and T2WI was 78.7%, 10.7% and 53.5% （X^2 =32.61, P 〈 0.001） on the 7th d after implantation and 95.8%, 54.3% and 82.9% （X^2 = 21.50, P 〈 0.001） on the 14th d. The signal of most VX-2 tumors on DWI was uniform and it was equal diffusion coefficient （ADC）. did not decrease on the 7th on the map of apparent The signal of VX tumors d after implantation, most of them slowly growing during the week following implantation without significant cell dying within the tumor. VX-2 tumors grew increasingly within 14 d after implantation but the signal of most VX-2 tumors on DWI or on the map of ADC was uniform or uneven and ADC of VX tumors decreased obscurely or slightly because tumor necrosis was still not obvious. On the 21th d after implantation, the signal of most VX-2 tumors on DWI or on the map of ADC was uneven because tumor necrosis was evident and ADC of VX-2 tumor necrotic areas decreased. The areas of viable cells in VX-2 tumors manifested a high signal on DWI and a low signal on the map of ADC. The areas of dead cells or necrosis in VX-2 tumors manifested low signals on DWI and low, equal or high signals on the map of ADC but they manifested high signals on DWI and on the map of ADC at the same time when the areas of necrotic tumor became liquefied or cystic. The border of tumors on DWI appeared gradually distinct and internal s展开更多
目的:探讨流动敏感交替反转恢复序列灌注成像(FAIR-PWI)对大鼠脑缺血后再灌注的评价。方法:使用GE 3.0T M RI成像仪,在完成T_1WI、T_2 WI、弥散加权成像(DWI)和FAIR-PWI序列后,对SD大鼠行暂时性右侧大脑中动脉闭塞(TMCA0)手术,分别在脑...目的:探讨流动敏感交替反转恢复序列灌注成像(FAIR-PWI)对大鼠脑缺血后再灌注的评价。方法:使用GE 3.0T M RI成像仪,在完成T_1WI、T_2 WI、弥散加权成像(DWI)和FAIR-PWI序列后,对SD大鼠行暂时性右侧大脑中动脉闭塞(TMCA0)手术,分别在脑缺血3h和再灌注3h及21h行重复上述MRI检查;最后进行病理学TTC染色观察梗死区域及范围。结果:TMCAO后3h时,患侧大脑半球DWI信号升高、FAIR-PWI灌注增加、且皮质相对脑血流量(rCBF)大于基底节区;再灌注3h及21h后,患侧大脑半球DWI信号面积(0.63±0.12cm^2、0.48±0.23cm^2)仍高于FAIR-PWI高灌注面积(0.51±0.26cm^2、0.34±0.44cm^2,P=0.01),皮质及基底节区rCBF较缺血时增加。TTC染色示梗死面积(0.42±0.78cm^2)小于DWI异常信号面积,而大于FAIR-PWI高灌注面积,且梗死区以基底节为主。结论:FAIR-PWI结合DWI能对早期缺血再灌注进行动态观察及半定量测量,可能为临床溶栓治疗方案的预后判断和随访提供重要参考,展开更多
文摘Some in vitro experiments have shown that erythropoietin （EPO） increases resistance to apoptosis and facilitates neuronal survival follow- ing cerebral ischemia. However, results from in vivo studies are rarely reported. Perfusion-weighted imaging （PWI） and diffusion-weighted imaging （DWI） have been applied successfully to distinguish acute cerebral ischemic necrosis and penumbra in living animals; therefore, we hypothesized that PWI and DWI could be used to provide imaging evidence in vivo for the conclusion that EPO could reduce apoptosis in brain areas injured by cerebral ischemia/reperfusion. To validate this hypothesis, we established a rat model of focal cerebral ischemia/ reperfusion injury, and treated with intra-cerebroventricular injection of EPO （5,000 U/kg） 20 minutes before injury. Brain tissue in the ischemic injury zone was sampled using MRI-guided localization. The relative area of abnormal tissue, changes in PWI and DWI in the ischemic injury zone, and the number of apoptotic cells based on TdT-mediated dUTP-biotin nick end-labeling （TUNEL） were assessed. Our findings demonstrate that EPO reduces the relative area of abnormally high signal in PWI and DWI, increases cerebral blood volume, and decreases the number of apoptotic cells positive for TUNEL in the area injured by cerebral ischemia/reperfusion. The experiment pro- vides imaging evidence in vivo for EPO treating cerebral ischemia/reperfusion injury.
基金The National Natural Science Foundation of China, No. 30070235, 30470508The Natural Science Foundation of Hunan Province, No. 08JJ5043+1 种基金The Science and Technolgy Foundation of Hunan Province, No. 06FJ3120, 2007SK3072the Medical Science and Technology Foundation of Hunan Province, No. B2006-159
文摘AIM： To investigate dynamical and image pathological characteristics of the liver on magnetic resonance （MR） diffusion-weighted imaging （DWI） in the rabbit VX-2 tumor model. METHODS： Forty New Zealand rabbits were included in the study and VX-2 tumor piece was implanted intrahepatically. Fifteen animals received two intrahepatic implantations while 25 had one intrahepatical implantation. DWI, T1- and T2-weighted of magnetic resonance imaging （MRI） were carried out on the 7th and the 14th d after implantation and DWI was conducted, respectively on the 21th d. Ten VX-2 tumor samples were studied pathologically. RESULTS： The rate of lump detected by DWI, TlWI and T2WI was 78.7%, 10.7% and 53.5% （X^2 =32.61, P 〈 0.001） on the 7th d after implantation and 95.8%, 54.3% and 82.9% （X^2 = 21.50, P 〈 0.001） on the 14th d. The signal of most VX-2 tumors on DWI was uniform and it was equal diffusion coefficient （ADC）. did not decrease on the 7th on the map of apparent The signal of VX tumors d after implantation, most of them slowly growing during the week following implantation without significant cell dying within the tumor. VX-2 tumors grew increasingly within 14 d after implantation but the signal of most VX-2 tumors on DWI or on the map of ADC was uniform or uneven and ADC of VX tumors decreased obscurely or slightly because tumor necrosis was still not obvious. On the 21th d after implantation, the signal of most VX-2 tumors on DWI or on the map of ADC was uneven because tumor necrosis was evident and ADC of VX-2 tumor necrotic areas decreased. The areas of viable cells in VX-2 tumors manifested a high signal on DWI and a low signal on the map of ADC. The areas of dead cells or necrosis in VX-2 tumors manifested low signals on DWI and low, equal or high signals on the map of ADC but they manifested high signals on DWI and on the map of ADC at the same time when the areas of necrotic tumor became liquefied or cystic. The border of tumors on DWI appeared gradually distinct and internal s
文摘目的:探讨流动敏感交替反转恢复序列灌注成像(FAIR-PWI)对大鼠脑缺血后再灌注的评价。方法:使用GE 3.0T M RI成像仪,在完成T_1WI、T_2 WI、弥散加权成像(DWI)和FAIR-PWI序列后,对SD大鼠行暂时性右侧大脑中动脉闭塞(TMCA0)手术,分别在脑缺血3h和再灌注3h及21h行重复上述MRI检查;最后进行病理学TTC染色观察梗死区域及范围。结果:TMCAO后3h时,患侧大脑半球DWI信号升高、FAIR-PWI灌注增加、且皮质相对脑血流量(rCBF)大于基底节区;再灌注3h及21h后,患侧大脑半球DWI信号面积(0.63±0.12cm^2、0.48±0.23cm^2)仍高于FAIR-PWI高灌注面积(0.51±0.26cm^2、0.34±0.44cm^2,P=0.01),皮质及基底节区rCBF较缺血时增加。TTC染色示梗死面积(0.42±0.78cm^2)小于DWI异常信号面积,而大于FAIR-PWI高灌注面积,且梗死区以基底节为主。结论:FAIR-PWI结合DWI能对早期缺血再灌注进行动态观察及半定量测量,可能为临床溶栓治疗方案的预后判断和随访提供重要参考,
