Long-Term Effects of Neonatal Hypoxia-Ischemia on Structural and Physiological Integrity of the Eye and Visual Pathway by Multimodal MRI
Long-Term Effects of Neonatal Hypoxia-Ischemia on Structural and Physiological Integrity of the Eye and Visual Pathway by Multimodal MRI
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DOI：
10.1167/iovs.14-14287
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发表时间：
2015-01-01
影响因子：
4.4
通讯作者：
Wu, Ed X.
中科院分区：
文献类型：
--
作者：
Chan, Kevin C.;Kancherla, Swarupa;Wu, Ed X.
目的.新生儿缺氧缺血是婴儿脑损伤的主要原因，并且可能经常出现视力障碍。虽然围产期护理的进步提高了存活率，但缺氧缺血性损伤的发病机制及其对视觉系统的长期影响仍不清楚。我们假设新生儿缺氧缺血可导致眼和脑视觉通路的慢性、MRI可检测的结构和生理改变。八只Sprague-Dawley大鼠在出生后第7天结扎左颈总动脉，然后缺氧2小时。一年后，使用7特斯拉扫描仪对视觉系统的T2加权MRI、钆增强MRI、铬增强MRI、锰增强MRI和扩散张量MRI（DTI）进行评估，并在对侧半球之间进行比较。在眼球内，全身性钆给药显示水玻璃体或血眼屏障渗漏仅在同侧左眼，尽管在双眼前房的房水动力学相当。双眼玻璃体内铬注射显示同侧眼视网膜完整性受损。尽管同侧视皮层完全丧失，但从对侧眼投射到同侧视皮层的视网膜丘和视网膜膝状体通路与对侧半球相比具有更强的顺行锰转运和更少的结构完整性破坏。高场，多模态MRI显示在体内的长期结构和生理缺陷的眼睛和大脑的视觉通路后，单侧新生儿缺氧缺血性损伤。其余的retinocollicular和retinogeniculate途径似乎更容易受到顺行变性的眼睛损伤比逆行，跨突触变性的视觉皮层损伤。
PURPOSE. Neonatal hypoxia-ischemia is a major cause of brain damage in infants and may frequently present visual impairments. Although advancements in perinatal care have increased survival, the pathogenesis of hypoxic-ischemic injury and the long-term consequences to the visual system remain unclear. We hypothesized that neonatal hypoxiaischemia can lead to chronic, MRI-detectable structural and physiological alterations in both the eye and the brain's visual pathways.METHODS. Eight Sprague-Dawley rats underwent ligation of the left common carotid artery followed by hypoxia for 2 hours at postnatal day 7. One year later, T2-weighted MRI, gadolinium-enhanced MRI, chromium-enhanced MRI, manganese-enhanced MRI, and diffusion tensor MRI (DTI) of the visual system were evaluated and compared between opposite hemispheres using a 7-Tesla scanner.RESULTS. Within the eyeball, systemic gadolinium administration revealed aqueous-vitreous or blood-ocular barrier leakage only in the ipsilesional left eye despite comparable aqueous humor dynamics in the anterior chamber of both eyes. Binocular intravitreal chromium injection showed compromised retinal integrity in the ipsilesional eye. Despite total loss of the ipsilesional visual cortex, both retinocollicular and retinogeniculate pathways projected from the contralesional eye toward ipsilesional visual cortex possessed stronger anterograde manganese transport and less disrupted structural integrity in DTI compared with the opposite hemispheres.CONCLUSIONS. High-field, multimodal MRI demonstrated in vivo the long-term structural and physiological deficits in the eye and brain's visual pathways after unilateral neonatal hypoxicischemic injury. The remaining retinocollicular and retinogeniculate pathways appeared to be more vulnerable to anterograde degeneration from eye injury than retrograde, transsynaptic degeneration from visual cortex injury.