Quantitative magnetic resonance spectroscopy reveals a potential relationship between radiation-induced changes in rat brain metabolites and cognitive impairment
Quantitative magnetic resonance spectroscopy reveals a potential relationship between radiation-induced changes in rat brain metabolites and cognitive impairment
复制标题
DOI：
10.1667/rr0735.1
复制
发表时间：
2007-11-01
影响因子：
3.4
通讯作者：
Robbins, Michael E.
中科院分区：
文献类型：
--
作者：
Atwood, Todd;Payne, Valerie S.;Robbins, Michael E.
为了测试磁共振波谱（MRS）在识别辐射诱导的脑损伤中的有效性，成年雄性Fischer 344大鼠接受分次全脑照射（40或45戈伊，每周两次，每次5-戈伊，分别持续4或4.5周）;对照大鼠接受假照射。全脑照射后12周和52周，大鼠进行高分辨率MRI和质子MRS。在任何时间都没有明显的病变或T-1或T-2加权图像的变化。这与照射后50周大鼠的组织切片中未发现大体变化一致。对分次全脑照射后12周获得的MR谱的分析也未能显示全脑照射和假照射大鼠之间脑代谢物浓度的任何显著差异（P > 0.1）。与此相反，对照射后52周获得的MR波谱分析显示，照射组和假照射组大鼠脑内几种代谢物的浓度存在显著差异，包括NAA/tCr（P < 0.005）和Glx/tCr（P < 0.001）比值的增加和mI/tCr比值的降低（P < 0.01）。在物体识别实验中，照射组与假照射组大鼠的认知功能在照射后14周无显著性差异（P > 0.1），但在照射后54周有显著性差异（P < 0.02）。这些研究结果表明，MRS可能是一种敏感的，非侵入性的工具，以检测辐射诱导的脑代谢物的变化，可能与辐射诱导的认知障碍后观察到的长期分割全脑照射。
To test the efficacy of magnetic resonance spectroscopy (MRS) in identifying radiation-induced brain injury, adult male Fischer 344 rats received fractionated whole-brain irradiation (40 or 45 Gy given in 5-Gy fractions twice a week for 4 or 4.5 weeks, respectively); control rats received sham irradiation. Twelve and 52 weeks after whole-brain irradiation, rats were subjected to high-resolution MRI and proton MRS. No apparent lesions or changes in T-1- or T-2-weighted images were noted at either time. This is in agreement with no gross changes being found in histological sections from rats 50 weeks postirradiation. Analysis of the MR spectra obtained 12 weeks after fractionated whole-brain irradiation also failed to show any significant differences (P > 0.1) in the concentration of brain metabolites between the whole-brain-irradiated and sham-irradiated rats. In contrast, analysis of the MR spectra obtained 52 weeks postirradiation revealed significant differences between the irradiated and sham-irradiated rats in the concentrations of several brain metabolites, including increases in the NAA/tCr (P < 0.005) and Glx/tCr (P < 0.001) ratios and a decrease in the mI/tCr ratio (P < 0.01). Although the cognitive function of these rats measured by the object recognition test was not significantly different (P > 0.1) between the irradiated and sham-irradiated rats at 14 weeks postirradiation, it was significantly different (P < 0.02) at 54 weeks postirradiation. These findings suggest that MRS may be a sensitive, noninvasive tool to detect changes in radiation-induced brain metabolites that may be associated with the radiation-induced cognitive impairments observed after prolonged fractionated whole-brain irradiation.