CREB1 and subarachnoid hemorrhage: In the field of exosomes, it has been reported that the BDNF/TrkB/CREB pathway was activated following treatment with miR-206 modified exosomes isolated from human umbilical cord mesenchymal stem cells (hucMSC) in a subarachnoid hemorrhage rat model [61], and enhancing BDNF level and balancing inflammatory response have been reported to be involved in the mechanism underlying the analgesic effects of hucMSC-derived exosomes [62].