Detection of cortical gray matter lesion in the late phase of mild hypoxic–ischemic injury by manganese-enhanced MRI
Detection of cortical gray matter lesion in the late phase of mild hypoxic–ischemic injury by manganese-enhanced MRI
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DOI：
10.1016/j.neuroimage.2007.09.009
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发表时间：
2008-01
期刊：
影响因子：
5.7
通讯作者：
Jian Yang;E. Wu
中科院分区：
文献类型：
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作者：
Jian Yang;E. Wu
早产儿的非囊性脑室周围白质软化症(PVL)正成为一种主要的病变形式。然而，由于常规MRI观察到的灰质病变的微妙和一过性，检测与后来的认知和行为缺陷密切相关的灰质(GM)病变具有挑战性。这项研究评价了锰增强磁共振成像(MEMRI)在7天龄大鼠轻度缺氧缺血(H-I)损伤(非囊性PVL的特征模型)中检测GM损害的价值。第1组(n=6)和第2组(n=8)分别于脑缺血后3h和7d腹腔注射MnCl2。对照组(n=6)未见MnCl2。分别行T1、T2和弥散加权成像(T1WI、T2WI和DWI)。动物处死后进行H&E染色和谷氨酰胺合成酶(GS)和锰超氧化物歧化酶(Mn-SOD)免疫组织化学染色，以对抗谷氨酸毒性和氧化应激。对照组H-I损伤后第7天MRI表现恢复正常。在第一组中，MEMRI提供了从第3天到第21天的增强和延长的GM病变检测。在第2组中，观察到类似的锰强化，使第8天能够检测到在第7天注射锰之前看不见的GM病变。这些体内锰诱导的GM病变增强被发现与GS和Mn-SOD免疫活性的增加有关。这些发现表明，MEMRI在检测轻度H-I损伤晚期常规MRI技术无法检测到的GM损伤方面具有潜在的实用价值。
Noncystic periventricular leukomalacia (PVL) in premature infants is becoming a predominant lesion form. However, detection of the gray matter (GM) lesions involved in this disease, which closely relate to the later cognitive and behavioral deficits, is challenging because of their subtle and transient nature observed by conventional MRI. This study evaluated manganese-enhanced MRI (MEMRI) for detecting such GM lesions in 7-day-old rats with mild hypoxic–ischemic (H–I) insult, a characteristic model of noncystic PVL. Group 1 (n=6) and Group 2 (n=8) were administered intraperitoneally with MnCl2at hour 3 and day 7 after H–I insult, respectively. Control Group (n=6) received no MnCl2. T1-, T2- and diffusion-weighted imaging (T1WI, T2WI and DWI, respectively) was performed. Animals were sacrificed for H&E staining, and immunohistochemical staining for glutamine synthetase (GS) and Mn-superoxide dismutase (Mn-SOD), which are two Mn-binding enzymes against glutamate toxicity and oxidative stress respectively in neurodegeneration. In Control Group, MRI appearance of H–I lesions normalized by day 7 after H–I insult. In Group 1, MEMRI provided the enhanced and prolonged GM lesion detection from day 3 up to day 21. In Group 2, similar Mn enhancement was observed, enabling day 8 detection of GM lesions that were invisible before Mn injection at day 7. These in vivo Mn-induced GM lesion enhancements were found to correlate with increased immunoactivities of GS and Mn-SOD. These findings suggest the potential utility of MEMRI in detecting the GM lesions that are otherwise undetectable using the conventional MRI techniques in late phase of mild H–I injury.