This study was performed to investigate the effect of bone marrow stromal cells (BMSCs) combined with green tea polyphenols (GTPs) on the blood-spinal cord barrier (BSCB) permeability after spinal cord injury (SCI) in the rat model. In the model of SCI rats, we found that the water content and the BSCB permeability were decreased by BMSCs and GTPs treatment, and their combination had a synergistic effect. Further, the motor function of rats was also greatly improved by BMSCs and GTPs administration. After treated by the combination of BMSCs and GTPs, SCI rats showed the up-regulated expression of tight junction (TJ) associated proteins claudin-5, occludin and ZO-1 by Western blot, which was more remarkable than that in the single treatment. The increased expression levels of claudin-5, occludin, and ZO-1 were the most obvious in the spinal cord microvessels using immunohistochemistry assay. This led to the conclusion that the combination of BMSCs and GTPs could decrease the BSCB permeability by up-regulating protein expression levels of claudin-5, occludin, and ZO-1. In addition, after BMSCs and GTPs administration, the results of Western blot and enzyme-linked immunosorbent assay (ELISA) revealed a significant decrease in protein expression level and the activation of nuclear factor-кB (NF-кB) p65. Our results indicated that combination of BMSCs and GTPs could improve motor function after SCI, which might be correlated with improvements in BSCB integrity, and that NF-кB might be involved in the modulating process.
