Comparative study of photobiomodulation therapy and low-intensity pulsed ultrasound for nerve regeneration and pain alleviation in an acute spinal cord injury model

Spinal cord injury (SCI) remains a significant medical challenge due to the complexity of its pathology. This study evaluated the effects of photobiomodulation therapy (PBMT) and low-intensity pulsed ultrasound (LIPUS) as non-invasive treatments for SCI. Thirty-six male Wistar rats were randomly assigned to 6 groups: control, SCI, PBMT, and LIPUS at 0.1, 0.3, and 0.5 W/cm2 intensities. SCI was induced using an aneurysm clip, and treatments began 30 minutes post-injury, continuing for 4 weeks. During the seventh week, no treatment was administered. Behavioral assessments, including the acetone and plantar tests for pain and the Basso-Beattie-Bresnahan score for locomotor function, were performed weekly from the first week until the study's end. At termination, lesion size was measured, and protein expression levels of glial fibrillary acidic protein (GFAP), transforming growth factor-β (TGF-β), phosphorylated glycogen synthase kinase-3β (P-GSK-3β), and neurexins were quantified via western blotting. Data were analyzed using Prism software. LIPUS at 0.5 W/cm2 emerged as the most effective treatment, enhancing motor function, reducing pain, and limiting tissue damage through modulation of GFAP, TGF-β, P-GSK-3β, and Neurexin1. LIPUS 0.3 and PBMT significantly reduced pain, while LIPUS 0.1 showed superior outcomes in movement recovery, indicating intensity-specific therapeutic effects.