Hypoxia-conditioned BMSC exosomes improve short-term spinal cord injury outcomes via the miR-615-3p/PDE4C-mediated cAMP/PKA pathway

• Hypoxia-conditioned BMSC-derived exosomes significantly enrich miR-615-3p, enhancing neuroprotective effects in spinal cord injury models. • The miR-615-3p/PDE4C axis activates the cAMP/PKA pathway, modulating calcium signaling and reducing mitochondrial-ER dysfunction. • Short-term treatment with hypoxic exosomes improves functional recovery, reduces lesion volume, and attenuates inflammation in a mouse SCI model. • These findings support the potential of hypoxia-conditioned exosomes as a novel therapeutic strategy for SCI, though long-term safety and efficacy require further validation.