Does Extracorporeal Shock Wave Introduce Alteration of Microenvironment in Cell Therapy for Chronic Spinal Cord Injury?

Study Design. Animal experimental study. Objective. To present experimental evidence for cell therapy for spinal cord injury (SCI). Summary of Background Data. In chronic SCI, the efficacy of cell engraftment has been known to be low due to its distinct pathology. Alteration of microenvironment was tried using extracorporeal shock waves (ESW) for chronic SCI, and the efficacy of cell therapy was investigated. Methods. A chronic contusive SCI model was made in 36 Sprague-Dawley rats. The rats were allocated into (1) control group (SCI only), (2) ESW control group (SCI + ESW), (3) IV group (SCI + intravenous transplantation of mesenchymal stem cells; MSCs), and (4) ESW + IV group (SCI + MSCs IV transplantation after ESW). ESW were applied at the energy determined by our preliminary trials. Engraftment of the cells and expressions of growth factors (brain-derived neurotrophic factor, neuronal growth factor) and cytokines (SDF-1, CXCR4, VEGF) at the epicenter were assessed. The Basso, Beattie, and Bresnahan locomotor scale was used for the clinical assessment. Results. The mean numbers of engrafted cells were higher in the ESW + IV than that in the IV with a statistical significance. The expression of SDF-1 was higher in the ESW groups than that in the control or IV group. CXCR4 was highly expressed in the transplanted groups. The expressions of growth factors in the treated group were higher in the treated group than those in the control group. However, various statistical significances were noted. The improvement of locomotor was higher in the transplanted groups than that in the control and ESW only group. Conclusion. At a given energy level, ESW presented more engraftment of the transplanted MSCs without any clinical deterioration in a chronic SCI. Based on this promising result and possible explanations, ESW may cause an alteration of the microenvironment for the cell therapy in chronic SCI.