This work was supported by the University of Basel, Department of Biomedicine, and the Swiss National Science Foundation (31003A_141007). Markus Saxer provided technical support.

Animal experiments were carried out in accordance with the European Communities Council Directive of 22 September 2010 (2010/63/EU) and were reviewed and permitted by Swiss authorities.
1. Setting up Organotypic Entorhino-hippocampal Slice Cultures
<ol>
	<li>Prepare entorhino-hippocampal organotypic slice cultures (EHOSCs) from postnatal day 4 (P4) mouse pups using the static incubation method4,11. Here, use C57Bl6 and CB6F1 mice.
	<ol>
		<li>Take approximately 30 min per mouse pu...

<ol>
	<li>Turner, R. C., Dodson, S. C., Rosen, C. L., Huber, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+science+of+cerebral+ischemia+and+the+quest+for+neuroprotection:+navigating+past+failure+to+future+success.">The science of cerebral ischemia and the quest for neuroprotection: navigating past failure to future success.</a> J Neurosurg. 118, 1072-1085 (2013).</li><li>Bacigaluppi, M., Comi, G., Hermann, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Animal+models+of+ischemic+stroke.+Part+two:+modeling+cerebral+ischemia.">Animal models of ischemic stroke. Part two: modeling cerebral ischemia.</a> Open Neurol J. 4, 34-38 (2010).</li><li>Woodhams, P. L., Atkinson, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regeneration+of+entorhino-dentate+projections+in+organotypic+slice+cultures:+mode+of+axonal+regrowth+and+effects+of+growth+factors.">Regeneration of entorhino-dentate projections in organotypic slice cultures: mode of axonal regrowth and effects of growth factors.</a> Exp Neurol. 140, 68-78 (1996).</li><li>Prang, P., Del Turco, D., Kapfhammer, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regeneration+of+entorhinal+fibers+in+mouse+slice+cultures+is+age+dependent+and+can+be+stimulated+by+NT-4,+GDNF,+and+modulators+of+G-proteins+and+protein+kinase.">Regeneration of entorhinal fibers in mouse slice cultures is age dependent and can be stimulated by NT-4, GDNF, and modulators of G-proteins and protein kinase.</a> C. Exp Neurol. 169, 135-147 (2001).</li><li>Bonnici, B., Kapfhammer, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spontaneous+regeneration+of+intrinsic+spinal+cord+axons+in+a+novel+spinal+cord+slice+culture+model.">Spontaneous regeneration of intrinsic spinal cord axons in a novel spinal cord slice culture model.</a> Eur J Neurosci. 27, 2483-2492 (2008).</li><li>Laake, J. H., Haug, F. M., Wieloch, T., Ottersen, O. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+simple+in+vitro+model+of+ischemia+based+on+hippocampal+slice+cultures+and+propidium+iodide+fluorescence.">A simple in vitro model of ischemia based on hippocampal slice cultures and propidium iodide fluorescence.</a> Brain Res Brain Res Protoc. 4, 173-184 (1999).</li><li>Rytter, A., Cronberg, T., Aszt&#233;ly, F., Nemali, S., Wieloch, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mouse+hippocampal+organotypic+tissue+cultures+exposed+to+in+vitro+&#8216;ischemia&#8217;+show+selective+and+delayed+CA1+damage+that+is+aggravated+by+glucose.">Mouse hippocampal organotypic tissue cultures exposed to in vitro &#8216;ischemia&#8217; show selective and delayed CA1 damage that is aggravated by glucose.</a> J Cereb Blood Flow Metab. 23, 23-33 (2003).</li><li>Bendfeldt, K., Radojevic, V., Kapfhammer, J., Nitsch, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Basic+fibroblast+growth+factor+modulates+density+of+blood+vessels+and+preserves+tight+junctions+in+organotypic+cortical+cultures+of+mice:+a+new+in+vitro+model+of+the+blood-brain+barrier.">Basic fibroblast growth factor modulates density of blood vessels and preserves tight junctions in organotypic cortical cultures of mice: a new in vitro model of the blood-brain barrier.</a> J Neurosci. 27, 3260-3267 (2007).</li><li>Camenzind, R. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preservation+of+transendothelial+glucose+transporter+1+and+P-glycoprotein+transporters+in+a+cortical+slice+culture+model+of+the+blood-brain+barrier.">Preservation of transendothelial glucose transporter 1 and P-glycoprotein transporters in a cortical slice culture model of the blood-brain barrier.</a> Neuroscience. 170, 361-371 (2010).</li><li>De Jong, G. I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cerebral+hypoperfusion+yields+capillary+damage+in+the+hippocampal+CA1+area+that+correlates+with+spatial+memory+impairment.">Cerebral hypoperfusion yields capillary damage in the hippocampal CA1 area that correlates with spatial memory impairment.</a> Neuroscience. 91, 203-210 (1999).</li><li>Cavaglia, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regional+variation+in+brain+capillary+density+and+vascular+response+to+ischemia.">Regional variation in brain capillary density and vascular response to ischemia.</a> Brain Res. 910, 81-93 (2001).</li><li>Chip, S., Nitsch, C., Wellmann, S., Kapfhammer, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Subfield-specific+neurovascular+remodeling+in+the+entorhino-hippocampal-organotypic+slice+culture+as+a+response+to+oxygen-glucose+deprivation+and+excitotoxic+cell+death.">Subfield-specific neurovascular remodeling in the entorhino-hippocampal-organotypic slice culture as a response to oxygen-glucose deprivation and excitotoxic cell death.</a> J Cereb Blood Flow Metab. 33, 508-518 (2013).</li><li>Stoppini, L., Buchs, P. A., Muller, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+simple+method+for+organotypic+cultures+of+nervous+tissue.">A simple method for organotypic cultures of nervous tissue.</a> J Neurosci Methods. 37, 173-182 (1991).</li></ol>

Animal experiments were carried out in accordance with the European Communities Council Directive of 24 November 1986 (86/609/EEC) and were reviewed and permitted by Swiss authorities. The authors have nothing to disclose.

With the methods presented here, hippocampal organotypic slice cultures can be used as a versatile tool to study plastic changes in neural tissue after injury. While organotypic slice cultures have been used in the past for studying neuronal reactions after ischemia6, 7 the new aspect of the simultaneous study of vascular changes significantly enhances the potential applications of this method. The induction of OGD or hypoxia alone can be applied by rather simple means in organotypic slice cultures and leads t...

The central nervous system is particularly sensitive to a loss or reduction of oxygen and glucose supply by the vasculature. Even a rather short interruption of blood supply to the brain can induce a permanent loss of function of the relevant brain areas leading to the typical stroke syndromes. In addition to the neuronal loss in the primary affected areas, there typically is additional delayed neuronal loss through secondary damage. Unfortunately until now, no neuroprotective treatment for the reduction of secondary neuronal death was available1. Research efforts for studying the mechanisms of secondary damage rely on the use of animal models of cerebral ischemia like middle cerebral artery occlusion and various thrombotic occlusion techniques (for a recent review see2). In parallel, also due to limitations and ethical concerns with the use of animal models, organotypic slice culture of various CNS tissues have been used that allow the study of neuronal reactions to various type of injuries3-5.
For studying the neuronal reaction under conditions that mimic ischemic brain injury, the model system of oxygen glucose deprivation (OGD) has been developed. In this model, slice cultures are temporarily exposed to a medium that lacks glucose and has been equilibrated with nitrogen gas in the absence of oxygen. With such a treatment, it is possible to induce neuronal injury and loss which is rather similar to the one observed after ischemic injury in vivo6, 7. In the hippocampus, such a treatment induces neuronal loss specifically in the CA1, but not in the CA3 area or the dentate gyrus of the hippocampus. In contrast, the study of vascular reactions in slice cultures so far has not been widely undertaken. An obvious reason is the lack of circulation and blood vessel perfusion in the slice culture model. However, we have shown previously that it is possible to maintain blood vessels in CNS slice cultures for several days8, 9.
The overall goal of this method is to not only monitor the fate of neurons after OGD but extend the study to the fate and remodeling of the vasculature which is an important part of the injury response. Until now such studies have required the use of animal experiments (De Jong et al., 1999; Cavaglia et al., 2001). In the protocol presented here, we will detail how such studies can be done in entorhino-hippocampal organotypic slice cultures challenged either with hypoxia or by excitotoxic lesions followed by analysis of both neuronal survival and blood vessel reactions. This protocol is based on a previously published study on this subject10 and can be useful for any laboratory interested in neurovascular interactions in the CNS.

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the analysis of neurovascular remodeling in entorhino-hippocampal organotypic slice cultures

Ischemic brain injury is among the most common and devastating conditions compromising proper brain function and often leads to persisting functional deficits in the affected patients. Despite intensive research efforts, there is still no effective treatment option available that reduces neuronal injury and protects neurons in the ischemic areas from delayed secondary death. Research in this area typically involves the use of elaborate and problematic animal models. Entorhino-hippocampal organotypic slice cultures challenged with oxygen and glucose deprivation (OGD) are established in&#160;vitro models which mimic cerebral ischemia. The novel aspect of this study is that changes of the brain blood vessels are studied in addition to neuronal changes and the reaction of both the neuronal compartment and the vascular compartment can be compared and correlated. The methods presented in this protocol substantially broaden the potential applications of the organotypic slice culture approach. The induction of OGD or hypoxia alone can be applied by rather simple means in organotypic slice cultures and leads to reliable and reproducible damage in the neural tissue. This is in stark contrast to the complicated and problematic animal experiments inducing stroke and ischemia in vivo. By broadening the analysis to include the study of the reaction of the vasculature could provide new ways on how to preserve and restore brain functions. The slice culture approach presented here might develop into an attractive and important tool for the study of ischemic brain injury and might be useful for testing potential therapeutic measures aimed at neuroprotection.

Oxygen glucose deprivation and hypoxia induce neuronal death and blood vessel reduction specifically in the hippocampal CA1 region. 
OGD or oxygen-deprivation alone for 15 min induced a strong induction of cell death as seen by propidium iodide staining specifically in the CA1 area of the hippocampus (Figure 3) similar as described previously7. With markers to visualize the network of blood vessels, it was found that blood vessel density and organization appeared similar to the c...

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The Analysis of Neurovascular Remodeling in Entorhino-hippocampal Organotypic Slice Cultures

A protocol for entorhino-hippocampal organotypic slice cultures, which allows reproducing many aspects of ischemic brain injury, is presented. By studying changes of the neurovasculature in addition to changes in the neurons, this protocol is a versatile tool to study plastic changes in neural tissue after injury.

Ischemic brain injury is among the most common and devastating conditions compromising proper brain function and often leads to persisting functional ...

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9.7K Views.  University of Basel. A protocol for entorhino-hippocampal organotypic slice cultures, which allows reproducing many aspects of ischemic brain injury, is presented. By studying changes of the neurovasculature in addition to changes in the neurons, this protocol is a versatile tool to study plastic changes in neural tissue after injury.