Analysis of reactive astrocytes and NG2 proteoglycan in ex vivo rat models of spinal cord injury

Background: The use of animals to model spinal cord injury (SCI) requires extensive post-operative care and can be expensive, which makes an altemative model extremely attractive. The use ofex vivo slice cultures is an alternative way to study the pathophysiological changes that can mimic in vivo conditions and support the 3Rs (replacement, reduction and refinement) of animal use in SCI research models.New method: In this study the presence of reactive astrocytes and NG2 proteoglycans was investigated in two ex vivo models of SCI; stab injury and transection injury. Stereological analysis to measure immunohistochemical staining was performed on the scar and injury zones to detect astrocytes and the chondroitin sulphate proteoglycan NG2.Results: The volume fraction (Vv) of reactive astrocytes and NG2 proteoglycans increased significantly between day 3 and day 10 post injury in both ex vivo models. This data shows how ex vivo SCI models are a useful research tool allowing reduction of research cost and time involved in carrying out animal studies, as well as reducing the numbers of animals used.Comparison with existing method: This is the first evidence of an ex vivo stab injury model of SCI and also the first comparison of immunohistochemical staining for injury markers within stab injured and transection injured ex vivo slice cultures.Conclusions: The use of organotypic slice culture models provide a simple way to study the cellular consequences following SCI and they can also be used as a platform for potential therapeutics regimes for the treatment of SCI.The authors acknowledge the facilities, scientific and technical assistance (Mr Mark Canney and Dr Kerry Thompson) of the Centre for Microscopy and Imaging at the National University of Ireland, Galway (www.imaging.nuigalway.ie), a facility which is co-funded by the Irish Government’s Programme for Research in Third Level Institutions, Cycles 4 and 5, National Development Plan 2007–2013. Funding for this project was provided by the Malaysia Ministry of Education and the College of Medicine, Nursing and Health Science at NUI Galway, Ireland.2020-03-2