Low-Intensity Pulsed Ultrasound-Induced Spinal Fusion is Coupled with Enhanced Calcitonin Gene-Related Peptide Expression in Rat Model

Low-intensity pulsed ultrasound (LIPUS) has been found to accelerate fracture healing. In this study, we analyzed the role of calcitonin gene-related peptide (CGRP) in a rat spinal fusion model treated with LIPUS. The results revealed that LIPUS significantly increases bone formation, and the process was coupled with elevated CGRP innervation. CGRP was located in fibrous tissue, closely surrounding the allograft and newly formed cartilage. The density of CGRP peaked at week 3 after surgery in both the control (non-LIPUS-treated) and LIPUS-treated groups. These results suggest that LIPUS might accelerate spinal fusion by promoting sensory nerve fiber innervation.