We, therefore, set out to develop a standardized mouse model to study recovery from stroke. Hypoxic–ischemic stroke is a well-described model first reported in 1960 in adult rats by Levine (1960), and has been used extensively in adult rats and mice as well as in

neonatal rodents. Hypoxia causes thrombosis on the side of unilateral common carotid occlusion, resulting in injury to the ipsilateral cortex, hippocampus, and striatum, but sparing the contralateral hemisphere, which exhibits normal perfusion during hypoxia (Adhami et al. 2006). We chose hypoxic–ischemic stroke because it is a high throughput model that allows behavioral testing to be performed on large groups of mice in parallel, minimizing the effects of Inhibitors,research,lifescience,medical day-to-day variability. Importantly,

it results in a significant neurological injury similar to that seen in disabling human stroke. Functional deficits have been reported in this model Inhibitors,research,lifescience,medical (Olson et al. 2004; Olson and McKeon 2004; Guzman et al. 2008; Andres et al. 2011) but so has stroke size variability (Kuan et al. 2003; Olson et al. Inhibitors,research,lifescience,medical 2004; Adhami et al. 2006). We, therefore, chose to develop a model for studying functional recovery after hypoxic–ischemic stroke in C57BL/6J mice, and investigated how stroke size variability affected a panel of functional tests in the weeks after hypoxic–ischemic stroke. C57BL/6J is the most commonly used mouse strain for both stroke and genetic models. We found that the hypoxic–ischemic stroke procedure was consistent between surgeons. The model did cause variable stroke size in our hands, ranging from negligible to large enough to cause fatality. We found that functional testing on day 1 after Inhibitors,research,lifescience,medical stroke with a 2-MeOE2 chemical structure simple and inexpensive horizontal ladder test (Metz and Whishaw 2002) can be used to define a set of mice with large, relatively homogeneous strokes that are suitable Inhibitors,research,lifescience,medical for long-term studies of functional recovery. In this group of mice, we detected deficits in horizontal ladder, automated gait analysis/Catwalk, rotarod, and elevated body swing

test (EBST) that lasted for weeks. The ladder and Catwalk tests could both be used to follow recovery for 3–5 weeks after stroke, and the rotarod and EBST tests demonstrated out a fixed deficit that did not improve over the 5 weeks of testing after stroke. Activity chamber testing did not record deficits after hypoxic–ischemic stroke. Materials and Methods Animals All animal procedures were reviewed and approved by the Stanford University Institutional Animal Care and Use Committee. C57BL/6J male mice (Jackson Laboratories, Bar Harbor, ME) were 5 months old at the time of surgery and were used for all studies except 2,3,5-triphenyltetrazolium chloride (TTC) staining, which was performed in 2-month-old female albino C57BL/6J mice. Hypoxia–ischemia model Mice were anesthetized by 2% isoflurane in 100% oxygen.