Effect of exosomes derived from mir-126-modified mesenchymal stem cells on the repair process of spinal cord injury in rats.

Abstract

To investigate the effect of the micro ribonucleic acid (miR)-126-modified mesenchymal stem cell (MSC)-derived exosomes (MSC-exos) on the repair process of spinal cord injury (SCI) in rats. MiR-126-modified MSCs were cultured, the exosomes were extracted, and a rat model of SCI was established. The Quantitative Polymerase Chain Reaction (qPCR) was carried out to detect the expression of miR-126 in the injured spinal cord, and the Western blotting (WB) was adopted to detect the expressions of the exosome-related molecules. Subsequently, the motor function recovery of rats was examined via the Basso, Beattie and Bresnahan (BBB) locomotor rating scale. The effects of miR-126 exosomes on the injury volume and NeuN retention following SCI were evaluated via immunohistochemistry. MSCs were able to package miR-126 into exosomes secreted. After SCI, the recovery of the hind limb function of rats was remarkably improved by miR-126-modified MSC-exos relative to the control group. Treatment with miR-126-modified MSC-exos remarkably decreased the injury volume, retained the neuronal cells, and triggered the axon regeneration following SCI. Besides, the expression of Ras homolog gene family member A (RhoA), identified as the downstream gene of miR-126, was downregulated in the group with miR-126-modified MSC-exos. Moreover, miR-126-modified MSC-exos activated the extracellular regulated protein kinases 1/2 (ERK1/2) pathway. MiR-126-modified MSC-exos protect neurons of rats with SCI, stimulates axon regeneration, and improves the recovery of limb motor function after SCI.