Conclusion
BMSCs-Exo play a protective role in spinal cord injury by inhibiting complement mRNA synthesis and release and by inhibiting SCI-activated NF-κB by binding to microglia.
Methods
Rats were randomly divided into three groups, Sham (treated with PBS), SCI (SCI injury + PBS) and SCI + Exo (SCI injury + BMSCs-Exo). Changes in the complement system between the three groups were assessed with the use of proteomics. The proteomic data were verified using reverse transcription-polymerase chain reaction (RT-PCR). In addition, the distributions of BMSCs-Exo in rats with SCI were detected by immunofluorescence. Moreover, SCI-activated NF-κB levels were determined using Western blot.
Purpose
Spinal cord injury (SCI) is a relatively common, devastating traumatic condition resulting in permanent disability. In this study, the use of exosomes derived from bone mesenchymal stem cells (BMSCs-Exo) as a cell-free therapy for the treatment of SCI in rats was investigated to gain insights into their mechanisms of action.
Results
SCI insult increased complement levels, including C4, C5, C6, C4 binding protein alpha and complement factor H. In contrast, the SCI + BMSCs-Exo group exhibited attenuated SCI-induced complement levels. Immunofluorescence assay results revealed that BMSCs-Exo mainly accumulated at the spinal cord injury site and were bound to microglia cells. Western blot analysis of tissue lysates showed that BMSCs-Exo treatment also inhibited SCI-activated nuclear factor kappa-B (NF-κB).