Department of Radiology, Chi Mei Medical Center, Liouying, Tainan, Taiwan.
Magn Reson Imaging. 2013 Sep;31(7):1174-81. doi: 10.1016/j.mri.2013.03.026. Epub 2013 May 1.
This study aimed to further investigate the effects of agmatine on brain edema in the rats with middle cerebral artery occlusion (MCAO) injury using magnetic resonance imaging (MRI) monitoring and biochemical and histopathologic evaluation.
Following surgical induction of MCAO for 90min, agmatine was injected 5min after beginning of reperfusion and again once daily for the next 3 post-operative days. The events during ischemia and reperfusion were investigated by T2-weighted images (T2WI), serial diffusion-weighted images (DWI), calculated apparent diffusion coefficient (ADC) maps and contrast-enhanced T1-weighted images (CE-T1WI) during 3h-72h in a 1.5T Siemens MAGNETON Avanto Scanner. Lesion volumes were analyzed in a blinded and randomized manner. Triphenyltetrazolium chloride (TTC), Nissl, and Evans Blue stainings were performed at the corresponding sections.
Increased lesion volumes derived from T2WI, DWI, ADC, CE-T1WI, and TTC all were noted at 3h and peaked at 24h-48h after MCAO injury. TTC-derived infarct volumes were not significantly different from the T2WI, DWI-, and CE-T1WI-derived lesion volumes at the last imaging time (72h) point except for significantly smaller ADC lesions in the MCAO model (P<0.05). Volumetric calculation based on TTC-derived infarct also correlated significantly stronger to volumetric calculation based on last imaging time point derived on T2WI, DWI or CE-T1WI than ADC (P<0.05). At the last imaging time point, a significant increase in Evans Blue extravasation and a significant decrease in Nissl-positive cells numbers were noted in the vehicle-treated MCAO injured animals. The lesion volumes derived from T2WI, DWI, CE-T1WI, and Evans blue extravasation as well as the reduced numbers of Nissl-positive cells were all significantly attenuated in the agmatine-treated rats compared with the control ischemia rats (P<0.05).
Our results suggest that agmatine has neuroprotective effects against brain edema on a reperfusion model after transient cerebral ischemia.
本研究旨在通过磁共振成像（MRI）监测和生化及组织病理学评估，进一步研究胍丁胺对大脑中动脉闭塞（MCAO）损伤大鼠脑水肿的影响。
MCAO 手术后 90min 进行手术诱导，再灌注开始后 5min 注射胍丁胺，术后再每天注射一次，共 3 天。在 1.5T 西门子 MAGNETON Avanto 扫描仪上，通过 T2 加权图像（T2WI）、连续扩散加权图像（DWI）、计算表观扩散系数（ADC）图和对比增强 T1 加权图像（CE-T1WI），在 3h-72h 期间研究缺血和再灌注期间的事件。在盲法和随机的方式下分析病变体积。在相应的切片上进行氯化三苯基四氮唑（TTC）、尼氏和伊文思蓝染色。
T2WI、DWI、ADC、CE-T1WI 和 TTC 均显示，MCAO 损伤后 3h 开始出现病变体积增加，24h-48h 达到高峰。TTC 衍生的梗死体积与最后成像时间（72h）点的 T2WI、DWI 和 CE-T1WI 衍生的病变体积无显著差异，除 MCAO 模型中 ADC 病变明显较小（P<0.05）外。基于 TTC 衍生的梗死的体积计算与基于最后成像时间点的 T2WI、DWI 或 CE-T1WI 衍生的体积计算相比，与 ADC 的相关性也更强（P<0.05）。在最后成像时间点，在接受 vehicle 治疗的 MCAO 损伤动物中，伊文思蓝外渗明显增加，尼氏阳性细胞数量明显减少。与对照缺血大鼠相比，胍丁胺治疗大鼠的 T2WI、DWI、CE-T1WI 衍生的病变体积以及伊文思蓝外渗和尼氏阳性细胞数量均明显减少（P<0.05）。
我们的研究结果表明，胍丁胺对短暂性脑缺血后再灌注模型的脑水肿具有神经保护作用。
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