Human menstrual blood-derived stem cells combined with a new 3D bioprinted composite scaffold for spinal cord injury treatment

Spinal cord injury (SCI) regeneration and repair is a worldwide medical issue, and stem cell therapy is an emerging treatment strategy. Previously, our research group found that transplanting menstrual blood-derived mesenchymal stem cells (MenSCs) can promote axon regeneration in rats SCI. However, the SCI pathological microenvironment inhibits stem cell survival after transplantation. The acellular spinal cord is the most similar to the spinal cord in terms of three-dimensional structure and natural biological activity, and it can efficiently regulate axon growth and promote synapse formation. Based on recent progress in the understanding of scar-free spinal cord repair in neonatal mice, it was postulated that in the acellular spinal cord microenvironment of neonatal rats, it would be more active ingredients to promote axon regeneration and inhibit glial scars, than in the adult rat. The hypothesis was formulated that a new 3D bioprinted scaffold with neonatal acellular spinal cord/GelMA hydrogel/MenSCs would efficiently repair SCI. The neonatal acellular spinal cord can provide a dual bionic microenvironment for axon regeneration, optimizing bioactive composition and microstructure, and the GelMA hydrogel guarantees the scaffold's mechanical properties. Then, using 3D bioprinting technology, the pore size of the scaffold can be precisely controlled, and the spinal cord conduction tract path may be stimulated. Moreover, a tissue-engineered spinal cord can be constructed by planting MenSCs in the pores. Overall, our hypothesis suggests that 3D bioprinted neonatal acellular spinal cord/GelMA hydrogel composite scaffold coupled with MenSCs might have more beneficial therapeutic effects on spinal cord injury rehabilitation.