Syringomyelia is a serious complication of spinal cord trauma, occurring in approximately 28% of spinal cord injuries. Treatment options are limited and often produce unsatisfactory results. Syrinx formation and enlargement are thought to be related to abnormalities of cerebrospinal fluid hydrodynamics, and an imbalance between fluid inflow and outflow, but the exact mechanisms are unknown. Perivascular spaces may play a crucial role in the development of syringomyelia by providing rapid access for excess fluid, or if not patent, by disrupting fluid outflow. However, their role in syringomyelia pathology remains unclear.
This study used transmission electron microscopy to investigate in detail the anatomical components involved in the flow of cerebrospinal fluid in the spinal cords of healthy SpragueDawley rats and in a rat model of post-traumatic syringomyelia.
We found that post-traumatic syringomyelia is associated with several abnormalities in the spinal cord tissue, including enlarged perivascular spaces, extracellular oedema, cell death and loss of tissue integrity, demyelination, and a localised loss of endothelial tight junctions indicating a disfunction of the blood spinal cord barrier, with increased pinocytotic transport across vascular walls. These structural abnormalities underlie the functional and pathological changes, such as altered fluid dynamics, and contribute to inadequate volume regulation in syringomyelia.
Discussion and Conclusions
Overall, this study supports the use of transmission electron microscopy for identification of morphological changes between healthy and diseased tissue at ultrahigh resolution. Our findings provide the basis for future investigations of the potential pathological role of the observed abnormalities in fluid flow disturbances and inadequate volume regulation in the central nervous system and point out potential avenues for the development of new treatments.