A novel model of trauma-induced cerebellar injury and myelin loss in mouse organotypic cerebellar slice cultures using live imaging

Background: Traumatic brain injury (TBI) induces significant cognitive deficits correlated with white matter injury, involving both axonal and myelin damage. Several models of TBI ex vivo are available to mimic focal impact on brain tissue. However, none of them addressed the study of trauma-induced myelin damage. New method: The aim of this study was to set up a novel ex vivo weight-drop model on organotypic cultures obtained from mouse cerebellum, a highly myelinated structure, in order to study the temporal evolution of cerebellar lesion and demyelination. The extent of injury was measured by propidium iodide (PI) fluorescence and demyelination was evaluated by loss of GFP-fluorescence in cerebellar slices from PLP-eGFP mice. Results: Live imaging of slices showed an increase of PI-fluorescence and a significant loss of GFP-fluorescence at 6 h, 24 h and 72 h post-injury. At the impact site, we observed a loss of Purkinje cells and myelin sheaths with a marked loss of myelin protein MBP at 72 h following injury. Etazolate, a known protective compound, was able to reduce both the PI-fluorescence increase and the loss of GFP-fluorescence, emphasizing its protective effect on myelin loss. Comparison with existing methods and conclusions: In line with the existing models of focal injury, we characterized trauma-induced cerebellar lesion with an increase of PI fluorescence by live imaging. Our findings describe a novel tool to study trauma-induced myelin damage in cerebellar slices and to test biomolecules of therapeutic interest for myelin protection.