McNally Melanie A, Lau Lauren A, Granak Simon, Hike David, Liu Xiaochen, Yu Xin, Donahue Rachel A, Chibnik Lori B, Ortiz John V, Che Alicia, Chavez-Valdez Raul, Northington Frances J, Staley Kevin J
Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, MA 02114, USA.
Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Harvard Medical School and Massachusetts General Hospital, Boston, MA 02129, USA.
Brain Commun. 2025 Apr 18;7(2):fcaf153. doi: 10.1093/braincomms/fcaf153. eCollection 2025.
Mild hypoxic-ischaemic encephalopathy is common in neonates, and there are no evidence-based therapies. By school age, 30-40% of those patients experience adverse neurodevelopmental outcomes. The nature and progression of mild injury is poorly understood. We studied the evolution of mild perinatal brain injury using longitudinal two-photon imaging of transgenic fluorescent calcium-sensitive and insensitive proteins to provide a novel readout of neuronal viability and activity at cellular resolution and . , perinatal organotypic hippocampal cultures underwent 15-20 min of oxygen-glucose deprivation. , mild hypoxia-ischaemia was completed at post-natal day 10 with carotid ligation and 15 min of hypoxia (FiO, 0.08). Consistent with a mild injury, minimal immediate neuronal death was seen or and there was no volumetric evidence of injury by MRI 2.5 weeks after injury ( = 3 pups/group). However, in both the hippocampus and neocortex, these mild injuries resulted in delayed and progressive neuronal loss by the second week after injury compared to controls; measured by fluorophore quenching ( = 6 slices/group , < 0.001; = 8 pups/group , < 0.01). Mild hypoxia-ischaemia transiently suppressed cortical network calcium activity for over 2 h after injury (versus sham, = 13 pups/group; < 0.01). No post-injury seizures were seen. By 24 h, network activity fully recovered, and there was no disruption in the development of normal cortical activity for 11 days ( = 8 pups/group). The participation in network activity of individual neurons destined to die was indistinguishable from those that survived up to 4 days post-injury ( = 8 pups/group). Despite a lack of significant immediate neuronal death and only transient disruptions of network activity, mild perinatal brain injury resulted in a delayed and progressive increase of neuronal death in the hippocampus and neocortex. Neurons that died late were functioning normally for days after injury, suggesting a new pathophysiology of neuronal death after mild injury. Critically, the neurons destined to die late demonstrated multiple biomarkers of viability long after mild injury, suggesting their later death may be modified with neuroprotective interventions.
轻度缺氧缺血性脑病在新生儿中很常见，且尚无循证治疗方法。到学龄期，30%至40%的此类患者会出现不良神经发育结局。人们对轻度损伤的性质和进展了解甚少。我们使用转基因荧光钙敏感和不敏感蛋白的纵向双光子成像研究了轻度围产期脑损伤的演变，以在细胞分辨率下提供神经元活力和活动的新读数。首先，对围产期海马器官型培养物进行15至20分钟的氧葡萄糖剥夺。然后，在出生后第10天通过颈动脉结扎和15分钟的缺氧（吸入氧分数，0.08）造成轻度缺氧缺血。与轻度损伤一致，未观察到立即发生的最小神经元死亡，并且在损伤后2.5周通过MRI未发现损伤的体积证据（每组 = 3只幼崽）。然而，与对照组相比，在海马体和新皮质中，这些轻度损伤在损伤后第二周导致延迟性和进行性神经元丢失；通过荧光团淬灭测量（每组 = 6片，<0.001；每组 = 8只幼崽，<0.01）。轻度缺氧缺血在损伤后超过2小时短暂抑制皮质网络钙活性（与假手术组相比，每组 = 13只幼崽；<0.01）。未观察到损伤后癫痫发作。到24小时时，网络活动完全恢复，并且在11天内正常皮质活动的发育没有受到干扰（每组 = 8只幼崽）。在损伤后长达4天内，注定要死亡的单个神经元参与网络活动的情况与存活的神经元没有区别（每组 = 8只幼崽）。尽管缺乏明显的立即神经元死亡且仅网络活动有短暂中断，但轻度围产期脑损伤导致海马体和新皮质中神经元死亡延迟且进行性增加。晚期死亡的神经元在损伤后数天内功能正常，这表明轻度损伤后神经元死亡有新的病理生理学机制。至关重要的是，注定要晚期死亡的神经元在轻度损伤后很长时间内表现出多种活力生物标志物，这表明它们的后期死亡可能通过神经保护干预措施得到改善。
