Towner R A, Zhdanov R I, Janzen E G
MRI Facility, Ontario Veterinary College, University of Guelph, Canada.
Free Radic Res Commun. 1993;19 Suppl 1:S211-8. doi: 10.3109/10715769309056s211.
CCl4 and related compounds, such as halothane, are metabolized by the liver to form free radical intermediates, which are thought to be implicated in the hepatotoxic response. Two to three hours following CCl4 exposure (i.p.) there is a localized edematous region surrounding the portal vein which is observable by proton MRI in vivo. Enhancement of the CCl4-induced edematous region was possible using Gd-DTPA, a paramagnetic contrast agent. However, with the use of a nitroxide contrast agent (3-PCA) there was no enhancement, but rather a significant diminution of the CCl4-induced edematous response. These results suggest that the nitroxide contrast agents, which are themselves free radicals, act as free radical scavengers and therefore reduce the formation of the CCl4-induced hepatic 'damage' observed in proton MR images.
四氯化碳及相关化合物，如氟烷，在肝脏中代谢形成自由基中间体，这些自由基中间体被认为与肝毒性反应有关。腹腔注射四氯化碳后两到三小时，门静脉周围会出现一个局部水肿区域，在活体中通过质子磁共振成像可以观察到。使用顺磁性造影剂钆喷酸葡胺（Gd-DTPA）可增强四氯化碳诱导的水肿区域。然而，使用氮氧化物造影剂（3-PCA）时，并没有增强，反而四氯化碳诱导的水肿反应显著减弱。这些结果表明，本身就是自由基的氮氧化物造影剂可作为自由基清除剂，从而减少在质子磁共振图像中观察到的四氯化碳诱导的肝脏“损伤”的形成。
