An innovative technology for in vivo imaging of the important biological processes involved in the injury and repair of spinal cords has been developed, paving the way for a better understanding of the pathology and potential treatment of spinal cord injury (SCI).
While imaging plays an important role in understanding spinal cord functions and its response to pathological insults and therapeutic procedures, there is currently no effective method to capture the injured spinal cord at the level of cellular processes without activating the immune response.
Conventional imaging techniques require the patients to have their spinal cord tissue removed to increase image resolution, or run the risk of triggering immune responses in spinal cord tissue, which may affect the disease process being investigated.
But now, through the efforts of a research team led by scientists from the Hong Kong University of Science and Technology (HKUST), they have demonstrated a new approach to achieve long-term, repetitive, stable, high-resolution, and inflammation-free in vivo spinal cord imaging in mouse models.
Previously in imaging, retaining the ligamentum flavum (LF) meant sacrificing the imaging quality – but through the new technique, the team applied iodixanol, an FDA-approved non-toxic compound, as an optical clearing medium for the imaging window and greatly enhanced its transparency as well as image contrast and resolution.
Compared with the prior methods, the iodixanol-based optical clearing technique allows the researchers to remove less tissue above the spinal cord without compromising imaging quality, significantly extending the number of imaging sessions to up to 15 sessions over 167 days.
“Considering the difficulties associated with long-term and repetitive spinal cord imaging, this innovation will be an important and widely used tool for the study of spinal cord injury,” said Professor Qu Jianan, who is an expert of optical engineering and science with extensive experience in in vivo linear and nonlinear optical spectroscopy and imaging of biological tissues from a variety of animal models.
“By avoiding surgery-induced inflammation, we can track microglia from resting to activation stages and understand its functional interaction with degenerating and regenerating axons in the spinal cord,” added Professor Liu Kai, whose research interests include the cellular and molecular mechanisms of axonal regeneration in the adult mammalian central nervous system.
“In vivo imaging in living animal models will reveal new biological insights leading to efficient therapeutic strategies for SCI treatment.”
