Abstract
The rodent hypoxia-ischemia (HI) model, referred to as the Vannucci model, is the most commonly used model for studying perinatal hypoxic-ischemic brain injury (Zhu et al., 2009; Vannucci and Hagberg, 2004). In the Vannucci model, brain injury is acquired by combining a permanent unilateral common carotid artery ligation with subsequent exposure to hypoxia (Rice et al., 1981). The Vannucci model was originally developed in rat pups at postnatal day (PND)7 (Rice et al., 1981), an age at which the development of the rat brain corresponds to that of the human infant at gestational weeks 32-34 (Zhu et al., 2009; Vannucci et al., 2009). The Vannucci HI model has since been adapted to mouse models of perinatal brain injury, and this has allowed the technique to be used with a broader array of genetically modified animals. Mice at PND9 have been the most commonly used, and these correspond to the human near-term infant (Zhu et al., 2009). In the present protocol, the Vannucci model has been adapted to serve as a model of preterm brain injury in C57bl/6J mice at PND5, an age where the development of the mouse brain corresponds to the brain of a human preterm infant (Zhu et al., 2009; Albertsson et al., 2014). The injury acquired with this protocol is characterized by local white matter injury combined with small areas of focal cortical injury and hippocampal atrophy (Albertsson et al., 2014).
Keywords: Mouse, Newborn, Brain, Hypoxia, Ischemia
Materials and Reagents
Equipment
Procedure
Note: The duration of hypoxia, the chamber temperature, and the age and strain of the mice are all factors that have significant effects on the brain injury outcome. In this model, we use 70 min of hypoxia (Figure 3). However, this hypoxia time might need to be adjusted empirically for each laboratory’s unique conditions.
Representative data
Figure 6. Representative data. Representative photomicrograph of a thionin/acid fuchsin-stained brain coronal section shows the degree of injury in the ipsilateral hemisphere (the right side) at 3 days after HI at PND5 with 70 min of hypoxia. Arrows indicate focal subcortical white-matter injury and the loss of hippocampus in the ipsilateral hemisphere of the mouse brain.
Notes
HI should be performed during the daytime when the dam is less active. This makes it more likely that the dam stays in the nest to keep the pups warm when they return after the surgery/HI. Otherwise, the pups might suffer from hypothermia that would influence the degree of brain injury degree and contribute to variation in the results.
Acknowledgments
This protocol was adapted from the previously published study of Albertsson et al. (2014). XW and AM research is supported by the Swedish Medical Research Council (VR 2008-2286 and VR 2013-2475 to XW), the Bill & Melinda Gates Foundation Grand Challenge Explorations and Global Health (OPP1036135 to XW), Swedish governmental grants to researchers in the public health service (ALFGBG-367051 and ALFGBG-367051 to XW), VINNMER-Marie Curie international qualification (VINNOVA, 2011-03458 to XW), and Wilhelm and Martina Lundgren (37/2013 to XW and vet2-26/2013 to AM).
References
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