Effect of exosomes derived from MiR-133b-modified ADSCs on the recovery of neurological function after SCI

To investigate the recovery effect of exosomes derived from micro ribonucleic acid (miR)-133b-modified adipose-derived stem cells (ADSCs) on neurological function after spinal cord injury (SCI) and its mechanism.The SCI model of rats was used and divided into the following 5 groups: sham-operation group, 4 d SCI group, phosphate-buffered saline (PBS) group, miR-control group and miR-133b group. At 96 h after operation, rats were euthanatized, and spinal tissues were removed. Next, the level of miR-133b was detected via reverse transcription-polymerase chain reaction (RT-PCR), and the expression of RhoA protein was measured via Western blotting. Moreover, expressions of proteins associated with the axon regeneration pathway, including phosphorylated-cAMP-response element binding protein (p-CREB), CREB, phosphorylated-signal transducer and activator of transcription 3 (p-STAT3) and STAT3, along with expressions of neurofilament (NF), growth associated protein 43 (GAP43), glial fibrillary acidic protein (GFAP) and myelin basic protein (MBP), were tested by Western blotting and immunofluorescence staining.The miR-133b mimics significantly upregulated the expression of miR-133b in adipose-derived stem cells (ADSCs), compared to blank group (p0.05). The expression of miR-133b was significantly decreased in 4 d SCI group compared with that in sham-operation group (p0.001). The RhoA expression was statistically increased in 4 d SCI group compared with that in sham-operation group (p0.001), and it was partially impaired by using miR-133b compared with that in 4 d SCI group (p0.001). Expressions of NF, GAP43, GFAP and MBP were remarkably higher in 4 d SCI group than those in sham-operation group (p0.01), and they were also significantly increased in miR-133b group than those in 4 d SCI group (p0.01). Besides, our data showed a significant increase of p-CREB/CREB, p-STAT3/STAT3, NF, GAP-43, GFAP and MBP in miR-133b group compared to those in 4 d SCI group, with statistical reduction of RhoA (p0.05).We showed that exosomes derived from miR-133b-modified ADSCs can significantly promote the recovery of neurological function of SCI animals through affecting the signaling pathway related to axon regeneration and expressions of NF, GAP-43, GFAP and MBP.