目的:探讨双眼盲大鼠听、视觉通路锰增强磁共振成像(ME MRI)的形态学改变,并与病理结果相对照,验证视听跨感觉通道重组(听觉代偿通路)的产生.方法:14只健康新生雄性Sprague-Dawley (SD)大鼠随机分为双眼盲组(Group A)与正常组(Group B) (每组n=7),采用视神经离断法使大鼠致盲,盲后4个月分别经两组大鼠的左侧内耳外淋巴注入0.4M MnC12,24h后比较ME MRI表现,观察是否建立听觉代偿通路,并与病理结果相对照,以帮助确定听觉代偿功能的产生.结果:ME MRI结果显示双眼盲大鼠双侧内侧膝状体、听皮质、外侧膝状体、上丘及视皮质的对比度均较正常大鼠增高,差异具有统计学意义,以听皮质较显著(P＜0.01),视觉中枢差异更加明显(P＜0.001).ME MRI表现与病理结果具有较好一致性.结论:新生大鼠致盲4月后,MEMRI改变结合病理结果,提示产生视听跨感觉通道重组(听觉代偿通路).%Purpose:To determine the establishment of visual to auditory cross-modal plasticity by manganeseenhanced MR imaging (ME MRI).Methods:Fourteen healthy male Sprague-Dawley (SD) newbom rats were randomly divided into two groups (n=7 for Group A and B).The optic nerve (ON) transection was performed in the 7 rats of Group A to obtain binocular deprived models and the 7 rats of Group B were chosen for the control study.Four months later,0.4 M MnC12 was injected into the rats in two groups via the left inner ear perilymph.Twenty-four hours later,auditory pathway and visual center of MEMRI were compared with that of normal rats to determine whether there were new auditory compensatory pathway and nerve fiber connection between visual and auditory pathway.And the demonstrations of MEMRI were compared with pathology results to identify the generation of auditory compensatory function.Results:The contrast-to-noise ratio (CNR) of bilateral medial geniculate nucleus,auditory cortex,lateral geniculate nucleus (LGN),superior colliculus (SC) and visual cortex in rats after 4 months of binocular deprivation were increased when compared with the normal rats,the differences were with more significance (P＜0.01) in auditory cortex,with the most significance (P＜0.001) in visual center (including LGN,SC and visual cortex).Conclusion:MEMRI could display the changes of auditory and visual pathways in binocular deprived rats,and demonstrate the generation of visual to auditory cross-modal plasticity (auditory compensatory pathway),which was confirmed by pathology result.
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