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 alternative 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.