Jithoo Arya, Penny Tayla R, Wen Shu Wen, Suthya Althea R, Pham Yen, Sutherland Amy E, Wong Connie H Y, Miller Suzanne L, McDonald Courtney A
The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia.
Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia.
Dev Neurosci. 2025 Mar 4:1-20. doi: 10.1159/000544994.
Perinatal stroke causes lasting neurological deficits and there are currently no effective treatment options. Established animal models of perinatal stroke do not always mimic the clinical presentation of neonatal injury or are technically challenging to perform. The photothrombotic (PT) stroke model is a minimally invasive method that replicates focal ischaemic injury. Few studies have applied the PT model in neonatal contexts, and none have examined both short- and long-term effects across varying injury severities. This study aimed to optimize a protocol to create a mild model of perinatal stroke and subsequently characterize injury progression, neuropathological impact, and motor deficits over time.
On postnatal day 10 we used the PT method to induce perinatal stroke in rat pups. Pups were exposed to various light exposure times (10, 20, or 30 min) to determine the optimal time needed to produce a mild and reproducible cortical stroke injury. Behavioural assessments were conducted on days 4, 10, 20, and 30 post-injury. Brains were collected for analysis on days 3 and 40 post-injury.
Three days post-injury, the 20 and 30 min group had significant focal lesions and microbleeds were present in each of the PT groups. All PT groups showed significant neuron loss in the peri-infarct region and the thalamus, and microglia activation in multiple brain regions. As 30 min of light exposure showed extensive cortical tissue loss (>70%), we excluded the 30-min group from long-term assessment. 40 days post-injury, the 10 and 20 min groups demonstrated significant tissue loss and neuronal loss in the peri-infarct region and thalamus, but only the 20 min group showed neuron loss in the hippocampus. The 10 and 20 min groups both demonstrated ongoing motor deficits.
Our results demonstrate that increasing light exposure time in PT stroke results in a more severe stroke phenotype. 30 min of light exposure resulted in a severe injury at only 3 days post insult, therefore, was not further investigated. 10 and 20 min of light exposure had a similar effect at 3 days, however, after 40 days the 20 min exposure time created a moderate injury phenotype. From this study, we propose that 10 min of light exposure is optimal to create a mild stroke phenotype and is associated with motor deficits and altered neuropathology. This injury phenotype provides a focal and reproducible insult, while still being mild enough to feasibly test therapeutics.
围产期卒中会导致持久的神经功能缺损，目前尚无有效的治疗方法。现有的围产期卒中动物模型并不总是能模拟新生儿损伤的临床表现，或者在技术上实施具有挑战性。光血栓形成（PT）卒中模型是一种微创方法，可复制局灶性缺血性损伤。很少有研究将PT模型应用于新生儿环境，并且没有研究考察过不同损伤严重程度下的短期和长期影响。本研究旨在优化方案以创建一种轻度围产期卒中模型，随后随时间推移表征损伤进展、神经病理学影响和运动功能缺损。
在出生后第10天，我们使用PT方法在幼鼠中诱导围产期卒中。将幼鼠暴露于不同的光照时间（10、20或30分钟），以确定产生轻度且可重复的皮质卒中损伤所需的最佳时间。在损伤后第4、10、20和30天进行行为评估。在损伤后第3天和第40天收集大脑进行分析。
损伤后3天，20分钟和30分钟组有明显的局灶性病变，且每个PT组均出现微出血。所有PT组在梗死灶周围区域和丘脑中均显示出明显的神经元丢失，以及多个脑区的小胶质细胞活化。由于30分钟的光照显示出广泛的皮质组织损失（>70%），我们将30分钟组排除在长期评估之外。损伤后40天，10分钟和20分钟组在梗死灶周围区域和丘脑中表现出明显的组织损失和神经元丢失，但只有20分钟组在海马体中显示出神经元丢失。10分钟和20分钟组均表现出持续的运动功能缺损。
我们的结果表明，在PT卒中中增加光照时间会导致更严重的卒中表型。30分钟的光照在损伤后仅3天就导致了严重损伤，因此未作进一步研究。10分钟和20分钟的光照在3天时具有相似的效果，然而，在40天后，20分钟的光照时间产生了中度损伤表型。从这项研究中，我们提出10分钟的光照是创建轻度卒中表型的最佳选择，并且与运动功能缺损和神经病理学改变有关。这种损伤表型提供了一种局灶性且可重复的损伤，同时仍足够轻微以便可行地测试治疗方法。
