Identifying glial scar tissue using infrared thermography: a spinal cord injury pilot study

Introduction: Glial scarring after a spinal cord injury (SCI) can represent both a physical and a molecular barrier for axonal regeneration and thus its removal has been found to be helpful in the recovery process. For this removal to be feasible in humans, an efficient method is needed to clearly identify glial tissue without inflicting more damage. Objective: To evaluate infrared thermography as a tool for identifying glial scar tissue in chronic SCI. Material and methods: An exploratory experimental pilot study was performed on Sprague-Dawley rats divided into sham and SCI (T9). All animals were subjected to a baseline thermography performed after a laminectomy that was either followed by closure of the surgical planes (sham group) or injury infliction (SCI group). Five weeks later, a second thermography was performed. Afterward, the spinal cord (T8-T10) was removed and processed for glial fibrillary acidic protein (GFAP) immunohistochemistry, which was used as a gold standard for identifying reactive astrocytes and glial scar. All animals received the same care throughout the study. Results: The thermography did not reveal a statistical difference for the baseline values (p = 0.24); however, a significant difference in thermography values was found 5 weeks later (p = 0.01). This difference significantly correlated with astrocyte counts at the site of injury (r = –0.57; p = 0.03, Spearman’s correlation). Conclusions: Infrared thermography could be useful to evaluate the extent of glial scar after SCI.