Abstract: Objective To investigate the effects of hyperbaric oxygen (HBO) on homing of exogenous bone marrow mesenchymal stem cells (BMSCs) after traumatic brain injury (TBI) in rats. Methods BMSCs were isolated and cultured with Ficoll density gradient centrifugation, and the surface markers (CD29, CD90, CD45, CD11b) of the third generation were identified with flow cytometry. The authenticated BMSCs were processed by the cell membrane fluorescent probe CM-DiI before transplantation. Thirty-six Sprague-Dawley rats were divided into Sham group (n=6), TBI group (n=6), BMSCs group (n=12), HBO+BMSCs group (n=12). The number and locations of homing of tracing BMSCs were observed under fluorescent microscope after frozen sections, and the expression of stromal cell-derived factor 1 (SDF-1) and CXC chemokine receptor type 4 (CXCR4) proteins were detected with Western blotting one and three days after BMSCs transplantation. Results The fluorescence-labeled BMSCs focused on the injured hemisphere, especially around the damaged brain tissue. The number of homing was more in HBO+BMSCs group than in BMSCs group at the same time (P<0.01), and increased in both groups three days after transplantation compared with those of one day after transplantation (P<0.01). The expression of SDF-1 and CXCR4 protein were more in HBO+ BMSCs group than in BMSCs group (P<0.05). Conclusion HBO can promote the exogenous BMSCs homing to damaged brain tissue in rats after traumatic brain injury, which is related to the enhancement of SDF-1/CXCR4 axis.

Key words: traumatic brain injury, hyperbaric oxygen, bone marrow mesenchymal stem cells, homing, rats