Temporal changes in magnetic resonance imaging in the mdx mouse.
Temporal changes in magnetic resonance imaging in the mdx mouse.
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DOI：
10.1186/1756-0500-6-262
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发表时间：
2013-07-09
影响因子：
1.8
通讯作者：
Lovering RM
中科院分区：
文献类型：
--
作者：
Pratt SJP;Xu S;Mullins RJ;Lovering RM
杜氏肌营养不良症（DMD）的临床特征是严重的，进行性的骨骼肌损失。DMD的mdx小鼠模型中的表型比DMD患者中所见的表型严重得多。然而，已经描述了mdx小鼠的“关键期”，在此期间，在生命的第2周和第5周之间存在肌肉无力和退化/再生的峰值。许多研究采用小动物磁共振成像（MRI）检查各种营养不良模型中的骨骼肌，但这些研究代表了时间快照而不是纵向视图。健康（野生型，WT）肌肉的体内横截面T2加权图像是均匀暗的，并且这种均匀性不随时间变化，因为没有疾病。我们和其他研究者在MRI上发现营养不良肌肉有明显的改变，在肌肉中有多个不均匀分布的局灶性高信号。在这里，我们使用MRI监测了5至80周龄的mdx小鼠。颞部MRI扫描显示在关键期后不久，在9和13周龄时异质性增加，此后异质性降低。第9周和第13周异质性百分比增加4.3倍，与mdx小鼠描述的早期关键期概念一致。年龄是mdx小鼠定量MR研究中的重要变量。mdx小鼠通常在关键时期进行研究，此时最接近DMD病理学，但这里的初步研究结果，尽管基于随时间推移仅对一只mdx小鼠进行成像，但表明MRI的变化可以在此期间后不久发生，此时肌肉仍在恢复中。
Duchenne muscular dystrophy (DMD) is characterized clinically by severe, progressive loss of skeletal muscle. The phenotype is much less severe in the mdx mouse model of DMD than that seen in patients with DMD. However, a “critical period” has been described for the mdx mouse, during which there is a peak in muscle weakness and degeneration/regeneration between the 2nd and 5th weeks of life. A number of studies have employed small animal magnetic resonance imaging (MRI) to examine skeletal muscle in various dystrophic models, but such studies represent a snapshot in time rather than a longitudinal view. The in vivo cross-sectional T2-weighted image of the healthy (wild type, WT) muscles is homogeneously dark and this homogeneity does not change with time, as there is no disease. We, and others, have shown marked changes in MRI in dystrophic muscle, with multiple, unevenly distributed focal hyperintensities throughout the bulk of the muscles. Here we monitored an mdx mouse using MRI from 5 to 80 weeks of age. Temporal MRI scans show an increase in heterogeneity shortly after the critical period, at 9 and 13 weeks of age, with a decrease in heterogeneity thereafter. The 4.3-fold increase in percent heterogeneity at week 9 and 13 is consistent with the notion of an early critical period described for mdx mice. Age is a significant variable in quantitative MR studies of the mdx mouse. The mdx mouse is typically studied during the critical period, at a time that most closely mimics the DMD pathology, but the preliminary findings here, albeit based on imaging only one mdx mouse over time, suggest that the changes in MRI can occur shortly after this period, when the muscles are still recovering.